KingRex is a Taiwanese company specializing in compact computer-based home stereo systems using Class T amplification.  Like the Trends Audio System, KingRex seems ideally tailored to computer desktop systems and audiophiles who wish to have a system in a small space.  Indeed, such a system is also ideally tailored for those audiophiles who have wives who don’t want to see the stereo.

You Want a Small Speaker System?

JohnBlue JB3 Speakers

I shall start this review with the John Blue JB3 loudspeakers.  The JB3 speakers seem to me to fit a niche market but are better than you would expect given their size.  First, these speakers  are much better than those shipped with the Trends Audio package, although the JB3 speakers are about 60% more money.  The JB3 speakers have a gorgeous piano lacquer finish and very nice round speaker grills that fit solidly into place, and a solid single pair of rear connectors and a front port.  Four soft gel pads fit under the speakers and can be moved around as desired.  The speakers employ a single 3-inch paper woofer with a plastic bullet whizzer cap.  They are intended to be used as desktop speakers or in a near-field configuration in a small room.

Removing my Audio Note AX Two speakers  – which have considerable bass depth for speakers in their size class — I had to adjust to the JB3′s comparative lack of bass response.  After about 50 hours, bass improved rather well.  And no, it wasn’t about my ears getting used to the speakers because I often used my AX Two speakers to review the KingRex components.

Single-driver speakers require no crossover and typically, immediately have an advantage in the midrange.  The JB3 can typically cover the midrange more accurately and more smoothly than can two-ways.  Single-driver loudspeakers, however, do have problems with dynamics, bass and treble because one driver can’t do everything and they often sound a little shouty, suffering from early dynamic compression which thins out the sound, so that one is left with a flat wall of sound rather than a solid 3D space.  But hey all speaker designs have trade-offs; we each choose the trade-offs you can live with.

The JB3 is a smart trade-off because in all likelihood, owners will choose to purchase a subwoofer.  For long term satisfaction I would argue that you will definitely need to purchase a sub, though to be honest I would argue that you would want to add a subwoofer with virtually any small two-way speaker in this price class,  and few of them will have the cohesiveness in the midrange that the JB3 loudspeakers offer.  Most speakers will be considerably bigger and won’t be suitable on a computer desktop.

On Loreena McKennitt’s The Muse album – vocals were crisp clean and clear.  Imaging and sound staging were superb – an advantage of single drivers and their very small cabinets.  Bass was limited but gave the impression of more than was really there.

The JB3 played at comfortable levels without audible issues but when pushed loud, Loreena’s voice began to break and there was audible sibilance as the speakers compressed.  In a small room in the near-field, they played acceptably loud and they gave a rather good portrayal of female vocals.

Introduction

On a recent Friday afternoon, a brown UPS truck rolled up to my door with a delivery.  While this in itself is not an unusual event at my house, things began to get a bit surreal when the driver asked where the loading dock was located.  Soon thereafter, I walked out to the truck to find a pallet containing four boxes of the Pass Labs Xs 150 amplification system with a combined weight of 600 lbs.  The truck, fortunately, had a hydraulic lift gate and was equipped with a pallet jack so the driver and I were able to get the pallet into my garage;  however, it required a visit by my son, an ex-marine, to get the amps unpacked and installed in my system.  At that point, I began to realize that I was perhaps dealing with something that was likely to challenge many of my preconceptions about the differences between directly-heated triode tubes and transistors.  As you may have gathered from some of my past reviews, I have a strong prejudice toward low powered, DHT tube amplifiers designed around very simple circuits executed with the best parts available, but I am getting ahead of myself so will start with a short description of the design of the Pass Labs Xs 150 amps.

Description

Nelson Pass has very strong beliefs with respect to how an amplifier should be designed, chief among these that it is much more important to limit higher order harmonic distortion than it is to seek artificially low overall distortion levels.  Harmonic distortion in a Pass amp is predominantly 2nd or 3rd order, not higher.  The relative proportions of one to the other will typically influence the final sound of a particular Pass design with pure 2nd, sacrificing some control in exchange for a more triode-like sound.  Pass designs tend to rely on massive power supplies and class A operation which generally means that his higher powered amps will be very large and heavy and run very hot.

In this application, each Xs 150 mono amplifier is comprised of two chassis, one containing the power supply which weighs 150 lbs and one containing the audio circuitry which weighs 100 lbs.  According to Pass Labs, the utilization of a separate chassis for the power supply lowers electromagnetic noise and allows the space for greatly enhanced storage capacitance and larger, quieter transformers.  The power supply employs banks of redundantly paralleled high speed/soft recovery rectifiers as well as highly sophisticated high frequency noise filtering.  The amp has both single ended and balanced inputs with the balanced input having an input impedance of 200 Ohms and negligible capacitance.  The unique JFET’s and MOSFET’s employed in the input stage are no longer available in the open market.  Cabling connecting the power supply and audio circuitry is included with the package and has very sturdy locking connectors.  Likewise, the binding posts are well designed and provide a snug fit while preventing over tightening.

The amps are conservatively rated at 150 watts at 8 Ohms and 300 Watts at 4 Ohms.  In practice, I was never able to get them to clip or otherwise misbehave.  They run in class A, so continuously dissipate 680 watts which makes them uncomfortably hot to the touch.  The audio circuitry is designed to be stacked on the power supply.  The units are provided with extremely effective feet which do an excellent job of isolation. They are also provided with adequate power cords but benefitted rather significantly from the use of Stage III Minotaur power cords.  They also benefitted from an extended break-in prior to any serious listening, namely 150-200 hours with continued but much less significant  improvement thereafter. However, even straight from the box, they sounded very good after two or three hours of warm up.

Line Magnetic is an intriguing brand out of Mainland China. The owner of the company has for many years been restoring Western Electric amplifiers, loudspeakers, and drivers and operating as an OEM manufacturer for other more mainstream audio brands. This seems to be rather common in China with many companies first serving as OEM makers and then eventually bringing out their own products. Shengya, Jungson, and Cayin are some of the more known mainstream audio brands. Line Magnetic is a little different however because as noted above, they clearly love the past and wish to bring back proven and loved designs with improvements and at lower prices. Jack Roberts noted some of the background of the company in the LM755 review.

When I moved to Hong Kong in 2011 I noted the staggering number of tube amps sold here, including most of the usual suspects in the tube world, a large number of DIY amps, and of course numerous Chinese brands that run the gambit of the excellent to the possible fire hazard. At the time I was looking at building an inexpensive audio system and wrote some articles titled “Reviewer on the Run” for Dagogo about building an entry level system.

One of the product lines I stumbled upon was Line Magnetic. The dealer here was selling well-established tube brands such as Rogue Audio and Melody along with Zu Audio speakers and a set of big ATC SCM 100 speakers. The massive 219IA Line Magnetic amp sitting in the middle of the room was hard to miss, as it was at least twice as tall as the other amplifiers in the store. So I wandered in, sat down, and listened. I was across the board impressed with the results I was hearing with both the Zu Audio speakers and with the difficult to drive ATC SCM 100s. I filed it away but at that time I didn’t want to make too heavy a commitment in a second audio system.

A few months later I happened by the store again and was again impressed with Line Magnetics, their at-the-time, one and only, tube CD player; I was so impressed I bought the player. I have been using the CD 215 for over a year and didn’t bother reviewing it until Tone Imports in the United States began carrying the model. You can read my review of the LM CD 215 for further information.

Time passed and as my situation here became more solid, I began looking to delve into higher end Single Ended amplification. One of my favorite amplifiers is the Audio Note Jinro. The Jinro is a 211 SET amplifier and is a copper wired version of famous Ongaku amplifier. Though I found that 300B, EL84, and other lower powered SETs offer a wonderful sense of tone and beauty as well as exceptional inner resolution, because of my more varied tastes in music the 211-based Jinro and Ongaku reigned supreme. The Jinro can rock and offers a wealth of beauty and magic in its own right that makes it and the Ongaku the gold at the end of the rainbow and about as hard to own given the five and six figure prices, respectively.

The problem of course is really wanting something you can’t afford. So we of the non-Sultan variety must find something just as good for less; or at least we tell ourselves it’s just as good for less. Still, the advice I often give to beginning audiophiles is to listen to the best regardless of whether you can afford it. Have the frame of reference in your back pocket and find something that truly rocks your world. So with the Audio Note 211 amps in mind, separating themselves from other tube amplifiers I have heard, I at least have a clearer picture of what I want in an amplifier.

A Magnetic Pull

The Line Magnetic 219IA wound up moving back into the picture; even though it doesn’t use a 211 tube it is nevertheless a more robust SET amplifier offering a considerable, for SET, 24 watts. I was taken by its ability to play big full tilt music with bass prowess while also sounding nuanced with nearly the subtlety of a good 300B.

A lot of amps seem to do one or the other – you have to choose between tone and beauty on the one hand, and power and drive on the other. People choose the tube type based on their personal sonic preferences. I know audiophiles who hate big power tubes and prefer 1.5 watt per channel 2A3 or 45s. 845 and 211 tubes provide big power, but are difficult to get right: With big power comes complexity in the parts, and bigger transformers are required which means far more weight.

Generally I hate big heavy amplifiers and the Line Magnetic 219IA is BIG and HEAVY. I groaned. The 219IA clocks in at 55kg (121lbs) and won’t fit in any normal audio rack. It’s at least two and half times as tall as most amplifiers though not particularly wider or deeper than most. The amplifier is built like a tank complete with the gunmetal paint steel chassis. I am usually skeptical of big and heavy and I also tend to prefer simpler amps with less switches. But there are exceptions and the 219IA is one of the exceptions.

Over a year of courtship

I auditioned the LM 219IA numerous times for over a year. I kept coming back to double and triple check that I wasn’t missing some kind of gross audible foible that was tricking me into liking her. I would try it against the other amps in the store and ultimately the big Frankenstein-looking 219IA won my shootouts.

I decided to buy the amp. I want to be clear that I purchased this amp prior to a formal review largely because Line Magnetic was not seeking reviews and the policy many companies in Hong Kong have is that reviewers must purchase the amp if they want to review them. Fortunately, the manufacturer allows returns so I was not too worried; should I not have liked the amplifier there were other choices.

Audio Note UK often takes flack from the peanut gallery on internet forums for their very high priced audio components. Many of us who live on things called budgets view $100,000+ components as crazy toys for the rich. However, over the years I have come to the conclusion that if I came across the bucks to spend such dollars the first company I would look to would be Audio Note UK.

Why?

Quite simply, they “get it.” They get what music reproduction should be and how to extract music from various sources and mix the elements of truth and beauty to draw you into wanting to continue listening to music even when you should be off doing something else.

Here I sit with the 8 watt per channel IZero integrated amplifier, which is Audio Note UK’s entry level integrated amplifier. The IZero uses four not often used ECL82 triode/pentode tubes and it operates in class A for the first four Watts then switches to Class AB1. Before all you pure class A single ended triode readers prepare to have your eyes roll in haughty derision, you may wish to hold your sneers back because if there is a class A/B push pull amp that will change your mind, the IZero is very likely to be it.

As many of you know Audio Note UK builds systems in a series of levels. When you see components called “Zero” it doesn’t exactly inspire much confidence. Then calling it IZero I began to wonder if Peter had lost his mind and started making iPod attachments, or maybe he is just a huge fan of movies wherein Will Smith fights robots. After all Peter did name one of his amplifiers “Jinro”, which is also very famous brand of Korean Soju.

Reviewing Audio Note UK’s performance level hierarchy, zero is named for a type of minimum technology that Audio Note feels can properly recreate quality sound. Transistor amplifiers are listed as a “Minus One.” This might be funny if it were not for the fact that the IZero makes a strong case against the majority of transistor amplifiers and the majority of much more costly transistor amplifiers.

So let’s start with the negatives as all audio products have them. First, the amplifier has 4 inputs, none of which includes a phono stage. There is no remote control available and there is no headphone output. Further there is only one set of speaker connectors and according to the manual it appears to be rated for a 6 ohm load, thus no 4 ohm and 8 ohm taps. I’m sure not coincidentally, Audio Note UK speakers are rated at 6 ohms. I’d mention the 8 watts but if you’re reading about Audio Note UK you’ve probably overcome endowment issues affecting many males in the audiophile world. And lastly it takes a while to get going. Turn the amplifier on and it’s about 15 seconds before any sound comes out and about 5 solid minutes before it stops sounding completely sucky. Yes I am trying out the word sucky. I suppose I should do my job and describe sucky. My analogy would be to that of old tube televisions. When they were first turned on and the colours would be dim and filled with purple fringes and nothing was quite right, then after awhile the tube would warm up and the picture began to get very good.

The IZero seems to kick in at about the 20-30 minute mark. So basically the IZero should be used as background music for the first half hour – turn it on, do your dishes, vacuum the carpets, take the dog for a hydrant trip, or crawl into the fetal position holding your knees rocking back and forth until all is right in your listening room, and the IZero is finally ready to deliver the goods.

This is one of the slower amps I’ve encountered to warm up and get going full stride. My Audio Note UK OTO Phono SE is pretty much ready to go in a couple of minutes. Peter Qvortrup does tell you this in the manual and boy he is not kidding.

I said lastly already but I want to add one more lastly, I promise for the last time. There is the whole Audio Note UK “could it possibly look any less exciting?” that they have going on. Oh sure it looks elegant and it’s nicely made and is an aesthetic match for arguably the wonderful DAC 0.1x or CDT Zero, but it hardly looks spectacular compared to a lot of amplifiers for similar or considerably less money.

Some of the amplifiers in this price range, especially from China, make you think George Patton could ride them over the Rockies . The IZero is 7kg and when you look at it next to some of the many boat anchor Chinese amplifiers on the market the IZero just looks so astoundingly unremarkable. It’s very difficult to shake what the eyes see and the ears hear.

As some of you know I recently purchased the Audio Space Mini 2SE EL34 based integrated amplifier operating in Class A/B push pull, and offering 15 to 30 watts of power. The amplifier is bigger, beefier, sexier has more features, offers superb build quality, and has a very good headphone output. Plus, it’s nearly $1,000 cheaper. The Audio Space is one of many superior sounding Push Pull integrated amplifiers along with Antique Sound Labs, Rogue Audio, Grant Fidelity, Line Magnetic, Melody, Triode Co that have push pull amplifiers that fall in the sub $2,000 price range. The Audio Space isn’t necessarily better than those others but wasn’t any worse and offered a more desirable feature set. So looking at the more expensive Audio Note UK and my eyes seeing the rather pedestrian aesthetics and non tank like build quality, I was somewhat skeptical.

Audio Note UK, however, gets it right. And what does that mean? It simply means that the dots are connected – everything that comes out of this amplifier sounds connected and “whole.” Vocals are a prime example. My Audio Space sounds quite nice in a big sound sort of way but doesn’t connect a singer’s vocal range as a complete whole in the same way that the IZero masters. The Mini-2SE sounds considerably more mechanical, disconnected, and ultimately less satisfying. And really it is at this point where the IZero was going to fall into an area of what I think should be viewed as a possible classic in the making if Audio Note UK can keep the price down.

It is difficult not to get carried away with excitement when you have an encounter with a wonderful sounding audio component, especially when it is affordable. If the sound is engaging it is easy to make sweeping conclusions, euphoric exclamations of the superiority of the product and one’s complete contentedness. Sound familiar? Most of us who have been in the game long enough have gone through this honeymoon phase of ownership several times.

Reviewers are no different, which is why I wait a period of time prior to writing my articles about audio components – usually. Occasionally the review schedule is shortened for a variety of reasons or I feel strongly enough about the known performance aspects of the product that I can draw conclusions. Such is the case with the Musical Fidelity V90-DAC and M1PWR Amplifier.

Giant Killers

You know what’s coming, don’t you? At least you think you know; the tried and sometimes true exclamation that a component is a “giant killer.”  Recently I read Malcom Gladwell’s David and Goliath, which is not so much about the Biblical battle as the circumstance of being an underdog. Gladwell’s assertion is that we vastly overrate the giant and underestimate the underdog. He alludes to examples of individuals, teams and even social movements which should have had no chance but which came out on top in competition with seemingly far more formidable foes.

So it is with audio components and the audiophile; we routinely overestimate the capacity of the “giant” represented by the component with serious bling, overbuilt construction, and/or a pedigree of excellence, and underrate the ability of the lesser heralded stereo maker with a nondescript box. This is a story about David and Goliath because it is about a little Class D amp and a little, low cost DAC which have gone toe to toe with far more formidable gear. Welcome to the world of Musical Fidelity audio components!

Never Paid Attention

How many components or audiophile companies have you rubbed shoulders with in your lifetime? Hundreds upon hundreds, I would assume, and I can relate. The eyes begin to gloss over at the sheer number of manufacturing and sales concerns in this niche market. I had seen the brand name Musical Fidelity many times but only recall the cute X-CAN series of tubular affordable components. As to reviewing the company’s products I was uninterested – that is, until I had to send back the Simaudio Moon Evolution 750D DAC/Player following  extended loan after review. I was stuck for a transport/player and in the hunt for an affordable but solidly performing substitute for the occasion when the big gun products were not in my room. Enter the unassuming M1-CDT Transport (MSRP $999 at the time) which I tried on loan from Randy Bingham, National Sales Manager for Musical Fidelity in North America. I had seen enough positive accolades to give it a spin, pardon the pun. Though it has taken a lot of work with cabling on every system to establish an acceptable performance level, the MCDT has performed admirably, though not with the same effortlessness and weighting on the music as the 750D.

I was even less prepared to consider Randy’s Suggestion that I write up the V90-DAC, a whopping $300 product. Whoo-eee, can you see my face lighting up with ecstasy at the thought? I deal with serious components, not introductory stuff – ok, except for when I need a cdp quickly! I didn’t really want to spend time writing about a bargain bin DAC, but the M1PWR Amp did intrigue me. It, too, was being heralded as somewhat of a shocker, an immense value added box. So, I capitulated in favor of reviewing both since it had been a couple years since I worked with a Class D amp. Technology creeps forward inexorably and I didn’t want to get too far outside the mainstream of Class D amp development. Could it be that something better had happened than the last time I tried Class D? I had worked with three well regarded Class D amps, namely the Jeff Rowland 501, Channel Island Audio D-200 and Wyred4sound; you won’t find a review of the Wyred4Sound amp because I had a short demo period, not a review. When push came to shove all came up short. They had elements of greatness, but Class D as a technology hadn’t arrived to seriously challenge Class A or A/B. I am stating now it has arrived! By that I mean I finally have been able to use Class D to build an impressive, low excuse audio system. I say “low excuse,” because none but the very highest echelon, typically over the $100k mark are what I would consider a “no excuse” system.

Quick Overview

A cursory examination of these products shows the V90-DAC to consist of a smallish silver box with diminutive aluminum face plate and two toggle switches on the front; the one on the left controls power On/Off and the other selects between the Input options detailed below. The rear is just as tidy with its four inputs and one set of single ended outputs.

The M1PWR is also a study in efficiency as with similar chassis construction in black face shows the power On/Standby on the left above a pin sized LED indictor and the Mono and Temperature indicators with attending LEDs on the right.  Upon startup the power LED (blue in power saving/Off mode) turns Orange (standby). During loud musical passages the indicator may flash orange prompting the lowering of listening level so as to prevent the amp from clipping.

The Manual explains the purpose of the red LED; “TEMP LED (red) will come on if the device is getting too hot internally. This could indicate excessively high current through the speaker outputs. If the TEMP LED comes on, maximum power output will be internally reduced to allow the device to cool down. A Flashing RED LED indicates the chip has reached upper temperature limit and although the unit may continue to work, it should be shut down to clear the fault.

Continuous operation into very low impedance/short circuit may cause the unit to shut down. Switch off the unit and check wiring and speakers themselves for short circuits. Allow the M1 PWR approx. 10 minutes to cool down before attempting to turn it on again.”

At no time during the review period did I drive the amps to the point where the Red LED was operative. Perhaps as a reviewer it is my prerogative to attempt destruction of an amp if it has protection circuitry, but I don’t see much sense in it. With all but the most difficult to drive speakers the output will be such that the listening level would be unhealthy to one’s ears and should not be maintained regardless of the limits of the amp.

The rear of the M1PWR provides 3.5mm low voltage power trigger, Stereo/Mono switch which changes mode only upon startup, Left and Right single ended inputs as well as Left and Right Loop Outputs (linked to the inputs so as to pass the signal unaffected directly to another amp or subwoofer), and one set of Left and Right speaker posts.

Rogue is a small but well known American audio company that is known for building affordable all-tube components. They have grown into a true high end company with products like the Apollo dual mono tube amplifiers that retail for $10,995 for the pair. Now Rogue also offers hybrid amplifiers, the newest being the Sphinx which use tubes and Class D outputs. I should confess at the start that I have not been a fan of  Class D amps when sold as high end amps, but I have been impressed with them in bargain components and as subwoofer amps. So, I was intrigued by the concept of a hybrid tube/Class D for such a bargain price. The Sphinx integrated amplifier is a one hundred watts per channel hybrid amp built and designed in the U.S.A for $1,300. These days it’s hard to really get your head around that statement. Every Rogue component is hand-built in Pennsylvania with what appears to be excellent build quality.

Description

The hybrid Rogue Audio Sphinx integrated uses two matched JJ/12AU7 triode tubes for the preamplifier tube circuit. The tubes form a mu follower design that is coupled to an OEM version of a pair of Hypex UCD180HG Class D amplifier modules for the output stage, and an oversized toroidal transformer supplying the amplifier power. It has an output of 100 watts into 8 ohms and 200 watts into 4 ohms, plenty of current here. It has a damping factor of greater than 1,000 which means the bass should be very tight, fast, and powerful. We know how important power supplies are in amplifiers and the Sphinx uses a hefty, that is for this price range, toroidal transformer.

Fit and finish is very nice for this price point also, and I like the way it looks, especially in silver. The Sphinx has three line source inputs and a moving-magnet phono input. I think the balance control on the Sphinx is a great feature that is missing on most modern line stages. The Emia Autoformer line stage I am using in my reference system at this time has an ingenious balance control and I have come to find it a feature that I would not be without. There is also an optional motorized remote volume control which I think most people would think is worth the additional $100.

For an entry level integrated it has another well thought out features in addition to the balance control — a moving magnet or hi-output moving coil phono stage that has 40 dB gain. Also included is a discrete headphone amplifier. The optional remote is a motor driven Alps volume control, which is the way my unit came. I should mention the remote only changes the volume.

The front panel is made of a 0.25-inch thick-brushed aluminum or anodized black plate. From left to right, you find an opening for the remote control receiver, then the POWER On/Off button. On either side of the POWER button, there are two LED’s. The one on the left is a blue LED that indicates the power is on. The one on the right is a yellow colored LED indicating the amplifier is in standby mode; to the right of that is a socket for a 1/4″ headphone jack. Then there are three nice knobs, the first is the SELECTOR switch, the second is the BALANCE control, and last, the VOLUME control.

On the back panel you find an IEC power socket, the main power switch, and three-way binding posts nicely placed on the far side of the back panel with enough space to use decent speaker cable. In the center moving from the left, the first pair of RCAs are the phono inputs and the next three pairs of RCA inputs are for line 1, 2, and 3. There is also a pair of fixed and variable line-level outputs to use with a power amp, a subwoofer, or maybe with the popularity of headphones, an external headphone amplifier.

This is a $1,300 integrated amp so there have to be some cost savings. The speaker binding posts are the less expensive plastic type with 3/4″ spacing. The RCA female connections are cost saving board mounted and not individual sockets mounted on the back panel, and the phono ground connection is just a Phillips head screw. Also all of the graphics are simply silkscreen printed on the case work.

Still, while it will never be called eye candy, neither does it feel cheap, light, or plasticky like so many things at this price point. I have two other integrated amps, the $4,000 Electrocompaniet PI 2D Prelude and the $1,000 Peachtree Audio Decco. Both of these have built in DACs and in fact, the Electrocompaniet has two DACs, although neither has a phono section. They both look more stylish on the outside than the Sphinx which looks a little dated in appearance by comparison. To me, that says that Rogue spent more on the unseen parts than most amps at this price range.

What the Sphinx lacks in stylish looks it makes up for in some really great, if somewhat old fashioned features. To start with, as mentioned above, it has a built in phono stage. This provides 40dB of gain which is more than enough for a MM or Hi-output MC cartridge. Next, it has a discrete headphone amplifier that works in a pretty neat way. You put it in the standby mode and the speakers don’t play but the head phone amp does and you can adjust the volume with the volume knob on the front panel. The remote is made of solid aluminum, and feels good in the hand. As mentioned previously, the remote does only two things, up and down volume; I wish it also controlled the balance. Speaking of balance, the inclusion of a balance control is a nice old fashion feature as well.

If you are a regular reader of Dagogo you know of my love for the sound of the Western Electric 300B vacuum tube. My Wavac EC300B is decked out with two NOS WE 300Bs, two NOS Sylvania 6L6GC driver tubes and a pair of NOS WE 435As. A few months ago it seemed it was time to replace the 6L6GCs and the 435As. When I did I was shocked by how much better my system sounded. So I thought with nearly 12,000 hours on them I should start to look around for some more WE 300Bs.

This turned out to be such a daunting task that I decided to see what was available in new 300Bs. The ones I had heard so far had been in the $300 to $800 price range and just weren’t in the sonic ball park with the Western Electrics. Still there were two or three I was hearing really good things about. One was the Sophia Electric’s Royal Princes 300B. I heard such good things from people I trusted that I just ordered a pair.

Sophia Electric is located in Vienna, Virginia, where they design, manufacture, and sell handcrafted vacuum tube Hi-Fi electronics. The company is led by Richard Wugang. Turns out that like me, Richard had found that the new-production 300B vacuum tubes didn’t measure up to the Western Electric, and he decided it was time to try to do something about it.

So in 2001 Richard went to Mr. Zhe Sheng Liu, a retired Chinese engineer, who had designed some 300B tubes in China under the All Music label. They established a relationship with the goal of building a 300B with the midrange magic of the Western Electric and at the same time to extend the frequency extremes. With Mr. Liu providing the engineering expertise, and Richard guiding the voicing of the tube, they thought they could reach this goal. Since 2001 they have made several models of the 300B; all were good but none up to now had retained enough of the midrange magic for yours truly. Still, I was hearing that with the Royal Princess they had done it!

The first thing I noticed when I unpacked these was that they came in a wooden box that looked just like the one that some of the later Western Electrics had come in. The second thing I noticed when I took the first tube out of the box: These 300Bs were much more substantial than the Western Electrics. They have a very solid and well-made feel to them. The glass of the Sophia Electric 300B was obviously both heavier and thicker than my Western Electrics and the ceramic tube sockets were a very nice touch.

One of the dangers of using 300B tubes is they do not have any kind of grove or key on the center pin on the tube to prevent incorrect installation. 300Bs simply use two larger pins and two slightly smaller pins for proper orientation; with most it is possible to force them in wrong with bad consequences for both amp and tubes. It’s a nice touch by Sophia that they have made the large pins enough oversized that they are too large to insert incorrectly into the tube socket.

Listening

When I started listening to Nelson Pass’ First Watt SIT-1 solid-state monoblock amps I dicovered early on that they were more like my Wavac EC300B than any amp I had heard. Likewise, from early on I knew that the Sophia Royal Princes 300Bs captured more of the Western Electric midrange magic than I had heard from any other 300B tube. By the way the Wavac EC300B SET with the Sophia Royal Prince 300Bs and the First Watt SIT-1 amps sounded even more alike.

I can’t think of any way to tell you about the sound of these wonderful tubes other than to compare them to my Western Electric. I can say without a doubt that they are better than all the other current production 300Bs I have heard in my system. The only frontrunner I know of that I have not heart is Pavane’s reproduction of the Western Electric and I hope to hear them soon.

So let’s talk about how the Western Electrics and the Sophia Royal Princess 300Bs sound compared to each other. The Sophias have a more fleshed out and slightly darker overall sound by comparison. To my surprise they also seem to play louder and bolder than the Western Electrics. The Royal Princess also have a richer timbre and seem to paint more vivid tonal colors.

By contrast in the midrange and upper bass the Western Electrics displayed ever so slightly more detail, are more delicate sounding, with a little more air. Images are more solidly defined with the Sophia Royal Princess, but at that slight cost of air. This is only by comparison to the Western Electrics, compared to all other 300Bs I have heard they excel in these areas.

The soundstage presentation is slightly different also. The Sophia Royal Princess is bolder with bigger scale, but more tightly focused while the Western Electric’s soundstage opens up with more air and more spatial information.

One of the goals of the Sophia tube design was to better the Western Electric’s frequency extremes instead of imitating them. I would have to say they have managed to extend both frequency extremes and to add weight to the bass and shimmer to the top end. There is no doubt that the Sophia Royal Princess plays a little further into the bottom octaves. By contrast he Western Electrics have more punch and speed in the upper bass region. The top end also has more tonal colors with the Sophia Royal Princes tubes which comes across as sweeter and silkier. Still, somehow the Western Electrics have slightly more air.

Both tubes play music with a great sense of musical realism and emotional involvement. The Sophias have an overall sense of drama when playing music that is captivating. By contrast the Western Electrics sound more relaxed, which is equally beguiling. I have come to feel that this sense of sounding alive and relaxed at the same time may be at the heart of fabled midrange glory of the Western Electrics. My system sounds more like Quad 57s that can play really, really loud with the Western Electric. With the Sophia Royal Princess in my system it is sonically more spectacular and at the same time tonally richer and more vivid.

Conclusion

The Sophia Royal Princess are exceptional 300Bs. For the first couple of weeks I had them in my system I thought they had bettered my beloved Western Electric 300Bs, but when I put the Western Electrics back in the system I was blown away by the WE’s special ability to sound really alive and relaxed at the same time.

I’m not a collector or an accumulator so I have always found it hard to understand people who like to own multiple phono cartridges and tubes. My first exception to that was the Benz Ebony TR and Miyabi Standard phono cartridges. Now that I think about it the differences in those two phono cartridges isn’t that different from the two 300B tubes. The Miyabi Standard is the more tonally rich and has a bigger sound whereas the TR sounds more like the Western Electrics. So I’m in the same predicament I was in with those two cartridges, that is before I got the Soundsmith SG-220 Strain-Gauge: I just can’t decide which of the 300Bs are best. I love them both, but in the end I love the Western Electric the most!

Manufacturer’s comment:

The Princess mesh and Carbon 300B tubes came before this Royal Princess 300B tube.  Each has its own characters.  Many reviewers have praised them to be superior or competing with Western Electric.  They are great value in the market place for different price range.  It is difficult to say they don’t have midrange, especially when the reviewer has not heard them yet.  The carbon 300B especially was praised to have WE like midrange.

In my recent review of the Sanders Sound Model 10c speakers (interested readers may also want to read my interview with Roger Sanders ), I mentioned that the one perceived weakness was a mechanical quality to the sound that both I, and visitors to my listening room, attributed to the Behringer active cross-over that is included with the speakers.  In an effort to improve on this, I explored a number of options.  I first learned there are a number of commercial enterprises (all quite small, I would imagine) that modify the Behringer, though I never got so far as to actually try any of them.  I also tried another, more expensive digital crossover, in the hope that it would have better sonics than the Behringer (it did).  However, credit for the path I ultimately took goes to Merrill Wettasinghe of Merrill Audio, whose Veritas monobock amplifiers are my current reference (for a recent review by my fellow dagogoan Ray Seda).  Merrill also owns the Sanders Sound speakers, and mentioned to Ron Robinson of Channel D audio our interest in replacing the Behringer.  Rob suggested what proved to be an elegant solution using his Pure Vinyl (or Pure Music) software.  I interviewed Rob a few years ago and while I had some familiarity with his products, I had no idea of their flexibility and broad utility.  Rob was kind enough to bring a system (see below) to my home for me (and Merrill, and others in my local audiophile circle) to audition; I was so impressed I pulled the trigger.  This article will not be a review of a particular product; rather, it will be more of a systems review, the goal of which is to share my exploration in the hope that it will prove beneficial to others.

Out with the old, in with the new

Channel D software (i.e., Pure Music and Pure Vinyl) does not run in PCs, so I first had to get an Apple computer.  Rob uses a Mac Mini for the music computer, and controls it remotely (and wirelessly) with a MacBook, via the built in Screen Sharing feature of the Mac OS.  I ordered a Mac Mini to use as the music computer; rather than buying a second Mac, I purchased an iPad to use for remote control.  Rob had explained that Pure Music or Pure Vinyl would provide the cross-over functionality, but not the “shelf function” which was needed to correct for dipole cancellation.  For this latter function Rob recommended a plug-in from Fab Filter (http://www.fabfilter.com/), which I promptly ordered.  Importantly, Pure Music and Pure Vinyl are designed to work with a variety of Plug-ins, making interaction between the two programs seamless.  As I will discuss later, Fab Filter offered another important function that is applicable to all systems, not just those with an active cross-over.

Crossing-over in the computer solved one problem — the Behringer — but created another (actually, two others).  Because high and low frequencies are separated in the computer — that is, before the D-to-A converter (“DAC”) — it is necessary to use a DAC with four outputs (i.e., left high, left low, right high, right low), rather than the usual two.  For some time now Rob has been using the Lynx Hilo AD/DA Converter for his own system, which is actively bi-amped.  (I learned from Rob that the active crossover feature has been part of Pure Vinyl since its development began in 2003 — it was not something added later — -though at that time he used a different multichannel DAC.)  As should go without saying, Rob chose the Hilo not just because of its four channels and built-in ADC, but also because he likes its sonics (about which I will have more to say later).  I ordered one.

Those of you who read my interview with Rob will recall that Channel D Pure Vinyl was originally conceived and developed as a way to overcome one of the major quality bottlenecks to LP playback: the RIAA filter.  The digital archiving part was a secondary feature that came along “for free.”  Once an LP has been archived, playback is akin to playback of a ripped CD, though with the added benefit of Channel D Pure Vinyl’s patented –and I might add, superb — graphical interface.  However, archiving is not necessary; Channel D Pure Vinyl also allows one to listen in real time.  The RIAA correction is performed using Rob’s proprietary digital filters.  There are thus three ways one can listen to vinyl.  The first is the traditional method, which is purely analogue.  In this method, the output of the cartridge goes to the phono preamp, which both amplifies the signal and performs the RIAA correction.  The signal then goes to a line level preamp (i.e.  line stage) for additional amplification and volume control, then passed along to the amplifier, and from there to the speakers.  The second approach is a hybrid, involving both analogue and digital steps.  As in the purely analogue method, the signal from the cartridge is sent to the phono stage for amplification and RIAA correction (in the analogue domain), but the signal is then digitized and sent to a computer for subsequent processing (for example, crossing over the high and low frequencies), and optionally, storage.  In the third approach the signal from the cartridge is sent to a phono stage which amplifies the signal, but does not perform the RIAA correction.  The amplified signal is then digitized (in an ADC), and sent to the computer which performs the RIAA correction and subsequent processing (such as cross over), both in the digital domain.  As in the hybrid approach, the digitized signal can be stored for future access.  Rob believes performing RIAA correction in the digital domain (i.e., the third approach) offers a sonic advantage over the traditional approach to vinyl playback.  As my setup required digitization of the analog signal, and because I was switching to Channel D Pure Vinyl for digital playback, I figured I might as well go all the way and perform the RIAA correction digitally, using the Channel D Pure Vinyl software.  As I mentioned, it is still necessary to use a phonostage to boost the small signal from the cartridge, but of course it must do so without also performing the RIAA correction in the analog domain.  I was unaware of such a device but — surprise surprise — Rob’s SETA phonostage is just what the doctor ordered.  It provides sufficient gain for even my low output (i.e., 0.2 mV) Miyajima Shilabe cartridge, and settings to match virtually any cartridge.  (As an aside, it is available with an optional board that performs analogue RIAA correction, for those who wish to take the traditional approach.)  I ordered a SETA, and now had everything I needed.

Here is a summary of the old and new systems:

I love finding unexpected pathways to performance, that is, methods that have potential to outperform expectations. Some are so unexpected that few audiophiles would try them because of the foregone conclusions, “It won’t work,” or “It won’t matter.” If it doesn’t involve something potentially harmful to the system, I’ll likely try it. Some of my favorite discoveries have come about this way.

One such discovery was doubling bi-wired speaker cables. It sounds like an idiotic idea to slap another full set of speaker cables on top of (parallel) to an already doubled set. That entails the use of two full bi-wire sets; in the case of the reliably superb sounding Clarity Cable Organic cables that means eight full cables! I can’t tell you how many engineering types, “know it all” types, skeptical types, etc. have rolled eyes, laughed, or were silent when I intoned that it is a superior way to hook up speakers. Do I care that they scoff? Not in the least, because I get to hear the results!

The reason I do so is because in my casual experimentation the total gauge of the speaker cable matters, and the more conductor (while maintaining a short signal path) the better. In short, if you have an identical wire in terms of conductor material, geometry and dielectric, doubling it up will improve its sound. I’m sure this violates all sorts of fancy electronic principles, but it works. I’m not most interested in proving electronic principles; I’m most interested in building superior sounding rigs, so my cables get doubled.

Might I find a cable someday which would as a standard bi-wired setup outperform the double bi-wired speaker cables? Sure, but then I would want to hear it in a double bi-wire configuration!

Now, if you are scoffing, sensing this is going to be a dumb article, please feel free to stop reading now because you likely will not take away much from it. You likely have already labeled me and condemned my perspective, so save your time. To the rest, who want a potentially useful insight into alternative systems to achieve unexpectedly good results, read on!

Mono Integrated

About five years ago I stumbled upon my first mono integrated amp, the Pathos Classic One. I first bought the amp to use traditionally as a stereo integrated. Following the geeky habit of reading through the Owner’s Manual, I discovered it was capable of being run in Mono mode! I thought it a swell idea and scoured the audiophile community to find only two others who had tried using two units for discrete Left/Right channel amplification. Not only did it prove efficacious, it became one of my favorite amplification schemes I have ever encountered. These two lovely Italian workhorses put out 170wpc into 8 Ohms and approximately 270wpc into 4 Ohms! I say “approximately” since Pathos didn’t even put the specifications for Mono mode in the Manual, as the function was seemingly an afterthought. After all, who would be foolish enough to try mono integrated amps? Are you beginning to get the gist of this article? It is the setup you don’t see, the one you would dismiss, which might be your ticket to glorious sound. Those little amps stayed with me five years, longer than any component or speaker I have owned.

Upon embarking on this review I was shocked to discover that the Musical Fidelity M6 500i is a dual mono integrated amp, literally two mono integrated amps in one chassis! My amazement increased when I learned that Antony Michaelson of Musical Fidelity has been designing such amps for decades. I’m sure that his eyes have been rolling furiously as he reads the above comments on cables. Antony does not suffer fools easily, and as I interviewed him the exasperation with lesser design minds was evident, as he stated flatly that cables are, “… one of the biggest confidence tricks ever foisted on the consumer.” According to Antony assessment of a cable is straightforward, the relation of the total resistance of the cable to the output impedance of the amp. One gets the feeling Antony is confident he could make coat hanger wires work as well as boutique cables.

Titan Design and Titanic Power

So, those wishing to consider this Musical Fidelity M6 500i should know that it is built solidly upon objective principles, such as the Titan Design. Antony explained that the Titan design is based on the principle of very low global feedback through subtle circuit and PCB layout design. In a Titan layout, high frequency distortion doesn’t climb nearly as high as with classic designs. In 2006-2008 Antony decided to build the ultimate circuit, which was a bridged Mono design, which is neutral in terms of distortion all the time. The goal is an amplifier absolutely neutral both objectively and subjectively.

I suggest that Antony has hit the mark, as to my ear the M6 500i is fantastically neutral sounding. When one has experienced the dryness of many Class D offerings, or the warmth of higher power tube brands such as Moscode or VAC, then “neutral” is not only conceptual but very real goal for some listeners. It shows itself in the dynamics being as evident as the tonality, the definition as noticeable as the coherence and fluidity of the sound, with no emphasis placed on any part of the audio spectrum. Put the M6 500i on an electrostatic speaker and one notices the speed associated with panel speakers. Put the amp on a higher efficiency dynamic speaker such as the Daedalus Audio Ulysses and the vibrancy, sometimes considered as forwardness, of the speaker is epitomized. Put it on a rock-your-world hybrid like the Vapor Audio Nimbus White and you will get well-defined and powerful response over the entire spectrum, as well as generously scaled soundstage.

A 500wpc amp in such a tidy package is music to this audiophile’s ears! I love big power amps; the cleaner and more powerful the better! But, as aforesaid, the simplicity of the dual Pathos integrateds was beguiling. There is a direct payoff sonically relative to system costs when one simply skips the preamp and extra set of cables for a fine integrated. The problem is that often the integrated with high end sensibility is unable to fulfill the promise of a big gun amp, which can drive nearly any speaker on the market effortlessly. The M6 500i resolves that issue.

Earlier this summer I first wrote about the wonderful Melody Valve P2688 vacuum tube line stage. As I had mentioned, accompanying the P2688 on the long journey to South Florida was a pair of Melody Valve MN845 vacuum tube Monoblock power amplifiers. These amplifiers are really something to behold. To my eyes, they are stunningly beautiful; and heavy (165 lbs each!) as they are beautiful, so much so that no level of my normal bribes could induce my buddies to assist getting these beasts up the stairs. I had to up the ante and throw dinner in as well.

Like its P2688 line stage stable mate, the Melody Valve MN845 mono power amplifier is at the top of the Melody line of 845 vacuum tube-based mono power amplifiers. The line includes the 21 watt M845 with a single 845 power tube, the 70 watt PM845 which utilizes a pair of 845s, and the top of the line MN845 which delivers 150 watts from a quad of 845’s. This would mean that the quad of 845’s driven in push-pull configuration would have to be pushed hard as they can in this amplifier in order to even get to the neighborhood of 150. While it still represents less than half of the power of my current reference, the Pass Labs X350.5, nonetheless I felt that it would make for an interesting pairing with the full range Air Motion Transformer Eficion F300 speaker system. This notion was largely based upon what I heard the Melody MN845s do in the Angel City Audio Room at RMAF 2013, as well as the fact that the Eficion F300’s are typically demonstrated with the similarly powered 125w solid state Class A Plinius SA103 power amplifier.

The MN845 is of the premium reference line designated as the “AN” line. This means that, as is the case with the superb P2688 line stage, the MN845 is constructed using a laundry list of premium parts; these include Mundorf M-Cap Supreme Silver and Oil caps., Nichicon Gold Tune Caps, Solen Gold Label Caps, and Melody Valve Audio’s proprietary Power Transformers with oversized OCC filaments. These huge beasts are finished to perfection in a black lacquer which makes for a quite stunning appearance. With an aggressive introductory price of $13,599, these are the subject of this review.

Getting Started

As I mentioned in the review of the Melody Valve P2688 line stage, the MN845 power amplifiers arrived last November. While the line stage was quite manageable in terms of positioning, the prodigious MN845 power amplifiers presented an interesting set of challenges during set-up. First of all, their larger than normal footprint (17” wide by 27” deep) was far and away too large for any amplifier stands I had in-house. I therefore had to temporarily place them on sets of cabinet doors I commandeered from office furniture in another room. This as it turns out was not a great way to introduce these huge heavy tube power amps to the household, but oh well. Later in the course of the review I remedied the situation by purchasing a couple of amp stands that could handle both the weight and the footprint. This was not an easy find.

Upon opening the packaging and unearthing the amps, I was very surprised to discover that they were shipped with the tubes left in the sockets. This may be the first such amplifier I have seen to be shipped in this manner. Everything was however, intact and in fine condition. It’s a real testament to the structural integrity of the amplifier as well as the engineering and quality of the packaging to accomplish this with such a heavy yet delicate payload. Unpacking and closely inspecting the amplifiers just served to ratchet up the excitement even further. As is the case with the P2688, the MN845s appear to have superb build quality. Their level of fit and finish only accentuate the fact that these are indeed the pinnacle of what Melody Valve has to offer. Most of the weight of the MN845 is in the form of very large transformers to the rear and center of the chassis. As is typical, all transformers are of Melody Valve’s own design and manufacture. The MN845 is configured with a total of seven tubes. Up front left to right is a Melody Valve OEM labeled 12AU7 input tube that is flanked by aluminum heat shields, the next tube is a shielded Soviet 5C8S rectifier tube, then lastly to the right is a Melody Valve OEM 2A3 (perhaps as first driver stage ahead of the 845s?). Directly to the rear of these tubes are two massive transformers all encased in black lacquer case work. Directly behind these transformers and in fact, nestled between the two transformers to the front and the single large transformer in the rear is the bank of four 845 power tubes. Each 845 is flanked by aluminum heat shields. The tubes employed in the review units are Melody Valve branded 845s that I understand are actually select Psvane units.

To the rear of the MN845s there is hook up capability for single ended as well as balanced input. There is a heavy toggle switch for power and a small rocker switch beside it that allows input modes to be switched between single-ended and balanced operation. The speaker binding posts appear to be of high quality as well.

The phono preamp is not the sexiest component in the system, at least as far I’m concerned. A little bit of a front-end component, kind of a middle of the pack component, it suffers from a touch of an identity crisis. But make no mistake about it – a miss matched or an inferior component at this stage can take the level of performance of a high-end system down into the drink.

Sexiness aside, I have grown to appreciate the task of amplifying the minute signal passed along by the cartridge and arm. Like carrying a thousand tiny wine glasses on platter balanced on your head up a flight of stairs, the delicacy and intricacy of the analog signal is seriously extreme.

Another person who feels much the same and then some about the analog sciences is Roger Gibboni, an ex aerospace engineer (You know, rocket science!). Roger Started to build Amplifiers in 2009. The current Rogers High Fidelity lineup includes the PA-1A phono preamp, two integrated amplifiers, and a high quality replacement AC cord, as well as a variety of replacement tubes. The Rogers High Fidelity website has his complete bio, well worth a read through.

While many designers are moving towards a smaller chassis for phono preamp design, Roger favors a full size approach. Generous in proportion, this true dual mono class A design employs three tubes per channel: a 6GH8, a 12AX7, and for the first gain stage either a 12AU7 or a 12 AX7. I had zero issue with insufficient gain. I could play as loud as I wanted with no running out of gas. The front panel knobs allow for cartridge loading, MC or MM select and a mute switch. My cartridge has a 0.3mV output.The voltage meters are retro cool and allow for simple diagnostics. I like the looks of the Rogers PA-1A though it will not win many beauty contests. But that is one man’s opinion. It’s overall appearance is inspired by vintage Amateur radios of which Roger is major enthusiast .

When my Behold phono preamp decides to operate, it can be satisfying. Clean and neutral enough with an upbeat dynamic, I have enjoyed this unit for some time despite its issue with reliability. (An article on the dependability of high-end audio is in the works.)

To dig a little deeper into what I look for in a phono preamp or any component for that matter, I’ll kick it off with dynamics. For starters, I like my steak tar-tar, my bourbon neat and my dynamics un-squelched. Here the PA-1A will shock your socks off. Listening to Stanley Clark’s “I Want To Play For You” From If This Bass Could Only Talk, a track I have been listening to digitally for years, sprang to life with real verve. The feeling of all the instruments pushing the tempo forward was evident right away, no straining to hear or feel the pulse of the music, the PA-1A simply sweeps you down the sonic river. The following tracks from If This Bass Could Only talk all followed suit. The system with the Rogers PA-1A in the chain is just brimming with life. Even the lively Behold sounds a tad bit flat by comparison.

To hear the PA-1A is to want one. This thing is so consonant with the music, all kinds of music. Every recording I pushed into service benefited from its presence. Must be a tube thing. I listen to far more mediocre recordings than reference show boaters. I have a slew of great rock recordings from the 70’s and early 80’s such as Deep Purples Machine Head. This album is full of great blues inspired music featuring Ritchie Blackmore at his blusiest . On the track “Maybe I’m a Leo” the PA-1A proves to be a component of such obvious neutrality, the information on the wax is presented unscathed yet imbued with a natural touch. These impressions are no doubt related to the PA-1A’s performance but there is also a real synergy with the Triangle Art turntable arm and My ridge as well.

“Haitian Divorce” from steely Dan Aja has real impact backing up a breezy Caribbean influenced groove helped along fluidly. “Do it again” from Steely Dan greatest Hits sounds simply awesome, at least as awesome as it has ever sounded. Though not exactly demo quality, I really enjoy digging as deeply into the grooves as possible from all my records, the good, bad or just plain ugly. What the Rogers brings on both tracks is a musical flow, a continuum uninterrupted by any form of grain, tonal anomalies, frequency deviations or any other audiophile approved criticisms one makes on such things.

The bass is extremely low in distortion if there is any distortion at all. I have a low tolerance for low-end anomalies, be it boomie-ness or on the other hand, a lack of weight and texture or a muddled mid bass transition to the mid-band. The Rogers just kills it within these parameters. Transient attack, hearty sustain and pitch perfect rendition of both tone and color are the real deal here. To reinforce this point, I inserted the Sunny Cable HSW-15 speakers into the mix. These 600 lb. a side speakers have a horn loaded mid band coupled to a 15 ” bass driver that operates up to 500 Hz. The big Sunny speaker devours any other speaker I have heard dynamically and are super transparent in the mid bass and low bass as well. With the Rogers in the soup the hyper revealing bass and transition into the mid band of the Sunny is put to a very challenging test. The Sunnys prevailed and unraveled the ball of tangled information with a deft touch. The shear amount of information passed on through from the Rogers made for some of the most compelling listening sessions I have had in a very long time. The 15” paper cone driver delivers prodigious yet extremely clean and effortless bass extension well into the 20Hz range. The Rogers PA1-A really allowed these qualities to shine.

The one area the Lansche 4.1 is preferred is in its ability to merge all the drivers into a seamless coherent whole. With the sunny I am at times reminded of its horn DNA with sounds occasionally localizing within the drivers and a little shouty-ness in the upper mid band. This is another area were the Rogers shines in the right circumstances. It’s ability to make instruments whole, with both tonal density and imaging specificity within the soundstage is beyond reproach. Transient speed, harmonic bloom, sustain and decay come together in perfect alignment and with great clarity striking a power full illusion of real instrument in real space.

The treble is a perfect amalgam of effortless resolution and sweet dewy liquidity. Vocals sounded more whole, more completely rendered thanks to the hyper resolution along with the liquidity of the upper treble harmonics. Listening to “Autumn Leaves” from Duke Ellington’s Indigos the violin is presented with greater texture with a sweeter tone. Sweeter than usual that’s for sure. I would hold off on calling it lush necessarily. The PA-1A can be rich on some recordings, though put on a disc with a lean tonal balance such as Pete Townsends Empty glass and one will find there is no added padding to smooth over the rough edges. This is all chalked up to a very low noise floor, stellar levels of uncolored resolution and a great dynamic range.

Compared to my Behold phono preamp, it is not much of a fight. The Behold sounds leaner, noisier, cooler in tone and edgier by comparison. The Rogers is also more coherent. I can follow lyrics with greater ease and complexity of densely orchestrated performances. All musical threads are easier to track for that matter. There is far less upper-mid band glare making cranking the system a stone cold gas. It is going to be a HUGE drag to give the PA-1A back.

I also ran the PA-1A in to my modest yet outstanding Melody MI-80 integrated amplifier (retail at the time of availability was $3500). The all tube rig won over all who heard it. Very liquid, great bass control and dynamics and a lively mid band had me re-evaluating investing 10 times as much on an amp! That said, the Pass Labs XA200.5 mono blocks really prove themselves as rock solid and crazy dynamic reminding me where all that extra cash went.

Is there any downside to the PA-1A, you may ask? The only thing I can think of is price, but even that is not fair as there are a bunch of 10K-50K priced phono preamps on the market these days. I have not heard most of them but It’s hard to believe the Rogers would be anything but a bargain at $7500 by comparison.

Despite a very short time with the PA-1A, I quickly went from having a crush, a syndrome I am susceptible to when getting new gear, to falling in love in a very short three weeks. Stellar sound, great build quality and user flexibility? It doesn’t get much better. Without hesitation, I would purchase the Rogers and never ever look back. The PA-1A is without question a huge success and should find wide reaching audience-A new reference

D’Agostino Master Audio Systems Momentum Integrated Amplifier

This had been a pretty sleepy summer. I spent more time with my two boys for which I am eternally grateful but I feel I have lost a bit of my edge in the process. Daddy brain they call it. The thought of getting clever and deep in the audio realm seemed a touch out of grasp. Perhaps my review of the Rogers PA-1A phono preamp took a little out of me. Great product to write about but the summer heat took over and cast a slight pall of laziness around the old Petan household. Perhaps fall would whisk in winds of change and my pilot light would fire up again. One thing was for certain, I was not counting on the D’Agostino Master Audio Systems Momentum Integrated amplifier falling into my lap for a prolonged run around the block.

Arriving in a hearty metal flight case, the packaging is what one should expect at this level. It really could not be any more straightforward getting the Momentum Integrated set up and playing. Simply screw in the cone shaped feet and stack the chassis on top of the power supply, attach the umbilical and power cord, plug it in and off you go. “God this thing is gorgeous;” you will mumble to your self after the brief set up. Gleaming blocks of diamond etched aircraft aluminum and some mad, cool looking copper slabs come together in encasing the watch bezel-like volume meter that looks more horological than audio. The meter mechanism is in full view front and center and really looks like a tourbillon, a device invented by Abraham-Louis Breguet in 1795 in order to deal with the earth’s gravitational pull on the mechanics of a watch. Still being mastered today, a tourbillon watch can start at $200k and head towards a million very easily. You thought high-end audio was expensive! What is really beyond slick is the VOLUME knob that rotates around the bezel of the volume meter. The mechanism is so smooth with just the right amount of knob feed back.

The front panel of the D’Agostino Master Audio Systems Momentum has six buttons named for every type of popular gizmo one may plug into it. And that copper is not just for show. They conduct heat three times more efficiently than steel or aluminum. This efficiency has allowed for the Momentum’s sturdy, but compact silhouette. Only providing for six XLR terminated connections, one must get plug converters to accommodate RCA terminated cables. On the right side of the front panels you find BASS and TREBLE controls. You read that right, BASS and TREBLE controls! The knobs are machined into a complex bolt-like shape. Each adjustment is met with a hearty thud, again great mechanical knob feel.

From the circular remote there is BALANCE control, POLARITY control, TONE control, POWER, MUTE and INPUT. I have not determined how sensitive the finish is, I have been polishing it every couple of days with a dry cloth just enough to remove fingerprints. There is a HT pass through input with unity gain. I only wish it was offered with a phono preamp. I hear one is in the works. The D’Agostino Master Audio Systems Momentum is nearly a Momentum Preamp And Stereo Amp in one chassis. They share a great deal of circuitry and at 200 watts on tap into 8 ohms, 400 into 4 ohms and 800 watts into 2 ohms it sounds every bit as powerful and then some. The separate power supply is machined from a solid block of aluminum, allowing for extreme physical and electro-mechanical integrity. The Momentum Integrated is also available in a stunning Black finish as well. For all the technical info available, please see D’Agostinoinc.com.

D’Agostino Master Audio Systems Momentum Integrated Amplifier

I am very familiar with Dan D’Agostino’s work. I date back to the KSA 150 amplifier and then the X32, and a X64 DAC. I also had the KPS 20i, KPS 25 CD players, a FPB 300 and FPB 600 amplifiers. Throw in a few preamps and I guess you could say I have a clear view into Dan’s past perspective on audio.

After being in possession of the D’Agostino Master Audio Systems Momentum Integrated amplifier for about two weeks, it dawned on me like a ton of bricks that it was time to start writing about this $45,000 gem from Dan D’Agostino Master Audio Systems. I typically would live with a component a bit longer before delving into the formal review. In this case the Momentum Integrated makes such an impression, such a compelling case for its singular superiority, I just had to get down to business.

Listening to Rush Moving Pictures, YYZ and Limelight were enough to get me off my mental couch, clear out the cob webs and let as many of you know as possible, what this magnificent piece of industrial art is capable of on every level.

I’ll start with the bottom line right up front. This thing is just killer. There is an absence of any type of distortion tampering with the signal — just pure rich, colorful tone and texture form top to bottom. Starting with the low end, on Limelight from Moving Pictures, Geddy Lee’s bass has such grip, such well resolved texture without compromising dynamic slam, like sledgehammers pounding you with both brutality and poise. Skrillex’s “Coast is Clear” from Recess possesses some of the scariest deep bass ever recorded and the D’Agostino Master Audio Systems Momentum remained unflappable. I have rarely heard the Lansche 4.1 speakers sound this rock solid and extended in the bass. “Show Me How to Live” from Audioslave’s self titled album just slithers and twists its way to audio nirvana. This track really does make its way to the monkey brain and flat out rocks. The level of composure the Momentum Integrated allows amongst the chaos is superb and offers complete confidence in the presentation.

I tend not to listen to a ton of audiophile recording so most of my impressions spring from recordings I am deeply committed to for the musical content rather than the audiophile parlor tricks. For instance, Black Sabbath’s Heaven and Hell sprang to life with impact and above all, mid bass clarity, giving the otherwise boxy sounding bass line a sense of texture and focus, clearing away so much of the hollow coloration that normally plagues this recording. Mid-bass notes are not defined through the D’Agostino Master Audio Systems Momentum by any type of euphony, coloration or over-emphasis. Simply tone, texture, transient accuracy and dynamic shading takes over and squeezes out the distortion leaving the easiest-to-follow bass lines I have yet heard.

Moving up the frequency ladder, the lack of distortion is on display with David Ostrika playing Mozart’s Scottish Fantasy on Classic Records CD via a streamer — you will be hearing a great deal about it soon, the notes despite being a tad shrill never jumped off the stage and slap you in the ear. The lack of distortion allowed the slight shrillness of the recording to simply come and go with little emphasis allowing one to sink deeper into the illusion. Ultimately, great music simply becomes greater through the Momentum Integrated.

Pass Labs XA30.8 class A stereo amplifier

In my review of the First Watt SIT-1 mono-blocks, I said, “If you’ve been an audiophile as long as I have, Nelson Pass is probably nearly a legend to you. I remember in my early twenties drooling over the Threshold amps. In the mid 80s he designed the real bargain amp of the day, the Adcom GFA-555 amplifier. For the past few years I’ve noticed as I attended audio shows, that I consistently enjoyed the rooms that used Pass Labs amplification.” Still, this the first review of a Pass Labs product for me. I have used a couple of Pass Labs phono stages, but never long enough for a review.

The reason for this review is kind of interesting. I knew I had a pair of Wayne Picquet’s restored Quad 57 coming in for a while, so I was trying to figure out what amp I wanted to use with them. Years ago when I owned the 57 my two favorite amps to use with them were the Bedini 25/25 and even better, the original 25-watt Electrocompaniet. Both of these were Class A transistor amps. I was not able to find anyone who had either of these two to spare, so I begin to look for a current production amp that was a low wattage Class A amp. There were less choices available than I had expected, but the just released Pass Labs XA30.8 looked perfect on paper. When you combined this with the fact that one of the constants at audio shows is how good rooms with Pass Labs amps sound, I requested an XA30.8 for review and the people at Pass Labs were nice enough to send me one.

In fact, they were so quick getting it to me that I had the XA30.8 in before the Quad 57 arrived. Even though 30 watts is a bit of overkill for my 104 dB efficient Teresonic Ingenium XR Silver, I decided to start the review using it with them. I also used the XA30.8 with the new 47 Labs Alnico Lens II bookshelf speakers and the Audio Note K/SPe.

Pass Labs’ new line of amps, the “XA.8” are designed to bring us amps that are even closer to the company’s “Xs” amps. Pass Labs says the “XA.8” amps were issued to celebrate the company’s 23rd Anniversary. The output stages of the .8 amplifiers bias more deeply into the Class-A operating region. The XA30.8 tops out at 40 volts and 20 amperes and like all the other XA models, produces 26dB of voltage gain. Their larger push-pull Class-A operating area is said to deliver lower distortion and additional loudspeaker control at ordinary listening levels. With the XA.8 they also uniquely molded each model’s front ends to the specifics of its output stage so that the nine amplifiers’ front ends vary in size, voltage, bias current, dissipation, and single-ended vs. push-pull bias distribution. They also used larger power supplies, more storage capacitance, more precise reference voltages, and new, larger heat sinks. The amp is really heavy and the heat sinks are fairly sharp, just a word of warning.

Description

The look of the Pass Labs XA30.8 has changed somewhat from the XA30.5. The faceplate in particular has changed. For last few years Pass Lab amplifiers have looked a lot like the X.5 series which has a two-part face plate. The front section had a circular opening framing the large round bias meter which was mounted on a second sub panel. Now, only the X.5 line retains this two-piece sculptured look. I’ll be honest, I really thought they looked classy. While the new XA.8 series looks really nice, I still liked the older look. The XA.8 series has a simple .75-inch front panel that is a single slab of aluminum with beveled edges and the large round bias meter centered on the front face. The meter shows the current draw of the amp. When the XA30.8 amp is operating in Class A the needle stays at 12 o’clock or very close to it. When the amp goes out of Class A the pointer may move to the right. It never did this with any of the speakers I used, regardless of how loud I played them, and I like loud music.

The XA30.8 is 19 inches wide and 21.25 inches deep, which means it won’t fit on a lot of people’s racks; I barely got it on mine because the rack is double wide. One other point, be sure it has lots of room to breathe; like all Class A amps it runs hot, thankfully not as hot as the First Watt SIT-1, probably due to its massive heat sinks. They look like something you would see on an amplifier that puts out several hundred watts. One warning: the heat sinks are extremely sharp as I learned the hard way. (Wait a minute, those cuts on your legs I saw the other day, I thought it was from the door of your sports car… -Pub.)

The only button on the Pass Labs XA30.8’s front panel is for power but around back you’ll find both unbalanced RCA inputs and balanced XLR inputs. It comes with U shaped jumpers in the XLR sockets. If you chose the RCA inputs then the XLR input sockets must have the U shaped jumpers connecting the input pin 3 to pin 1, ground. You will also find four massive speaker cable binding posts that unlike the X.5 amps, they do accept banana plugs, the main AC power switch, a 5 Ampere fuse socket and below the fuse is an IEC power cord receptacle. The last thing on the back is the one I was most thankful for, two big, heavy weight handles. Come to think about it why doesn’t everyone put them on the back instead of the front.

Setup

My reference system consist of the AMG Viella V12 turntable, Soundsmith SG-220 Strain-Gauge cartridge, Emia Remote Autoformer, Teresonic Ingenium XR speakers with Lowther DX4 silver drivers, High Fidelity Cables CT-1 and CT-1 Ultimate Reference interconnects, speaker cables, and power cables plugged into a HB Cable Design PowerSlave Marble. The amp the Pass Labs XA30.8 replaced was my beloved Wavac EC-300B with NOS Western Electric 300Bs and NOS Western Electric front end tubes. When I say beloved, I like this amp so much that I built my system around it.

With a shipping weight of 106 pounds the hardest thing about setting the Pass Labs XA30.8 up was unboxing it and getting onto my Box Furniture Company D3S Audio Rack. With it in the system I plugged an iPod into the Emia Remote Autoformer and let it play for the Labor Day weekend. I figured I got about 100 hours on it while I watched baseball, college football and enjoyed a day in the Napa Valley. It continued to slightly improve for the next couple of hundred hours.

Breaking-In and Warm-Up

The Pass Labs XA30.8 amp requires a lot of power; it draws 375 watts from your AC. So, it should be no surprise that it takes a while to break-in. This amp was brand new and when it was first turned on it’s got the new electronics smell that I have noticed before with some new equipment. By the way when it goes away the amp is more than half way broken-in. Now don’t get me wrong the XA30.8 sounds great right out of the box but just slightly veiled. These veils will be lifted with time.

Warm-up is an issue I seldom talk about. My Wavac EC300B sounds great in about 15 minutes and I never turn off my Electrocompaniet in the other system. Because of the heat and draw of the XA30.8 you will probably want to make use of that standby switch. The amp takes nearly an hour to come to life when coming out of standby but if you turn it completely off with the switch on the back, then it’s a different story. It takes at least half a day of playing to come around.

Pass Labs Xs 300 Dual Chassis mono amplifiers

This review is about the fabulously over-the-top Pass Labs Xs 300 monoblock amplifiers – although how can you even call them “monoblocks” when each channel comes in two hulking metal enclosures? Pass Labs calls them “Dual Chassis Monoblocks”, but that doesn’t come close to fully describing this 298-pound-per-side power plant.

So, how did I get so lucky?

I’ve now had the Pass Labs Xs 300 in my system for four months and finally have the opportunity to reflect on the experience. One of the first thoughts that popped into my mind was “How did I get so lucky?” I suspect it’s a combination of things, including my experience with amps, my electrical power setup, and my speakers. Let’ start with my experience with amps.

My amp reviews have been almost completely focused on high power amps. I’ve reviewed and/or owned the Proceed HPA-2 And HPA-3 stereo amps, Mark Levinson 350 stereo amp, Plinius SA-201, Sphinx Project Eighteen monoblocks, XLH M-2000 monoblocks, Rotel RB-1092 stereo amp, ShengYa PSM-600, Pass Labs X-600.5 monoblocks, Electrocompaniet Nemo monoblocks and Electrocompaniet Nada monoblocks. Prior to receiving the Pass Labs Xs 300, I ran the Electrocompaniet Nemo monos (600/1200 wpc at 8/4 ohms) and the Electrocompaniet Nada monos (400/800 wpc at 8/4 ohms) in biamp mode to drive my Vivid Giya G1.

Given the high power amps I run, my electrical system is pretty robust. My front-end is powered via a dedicated 15-amp electrical circuit using 2 different duplex outlets: one Wattgate 381 Gold outlet and one Walker Audio High Conductivity outlet. An Isoclean PT 3030G III Isolation transformer connected via a Isoclean Super Focus power cord runs from the wall outlet to a Lessloss Firewall. Lessloss DFPC Signatures from the Firewall power my front end. Each of the left and right Nemo and Nada monoblock pairs is powered by its own dedicated 20-amp electrical circuit. The outlets for the two 20-amp circuits are Walker Audio High Conductivity outlets and the power cords are Lessloss DFPC Signatures combined with two additional Lessloss Firewalls – one for each circuit. During the review I also used A.R.T. Super SE power cords, speaker cable and interconnects (review to come) with the Xs 300, to great effect.

Finally, the Vivid Giya G1 sounded great with virtually any kind of amp, but nuanced high power amps really make them sing. I’ve been powering them in passive biamp mode with my Electrocompaniet Nada’s handling the mids and treble, and my Electrocompaniet Nemo’s handling the bass. This is both a good fit and a stiff challenge for the Pass Labs Xs 300, in that at 300 wpc I can compare them directly against the 600 wpc Nemo’s and the 400wpc Nada’s individually, as well as those amps used in biamp mode at 1,000 wpc. In addition, toward the end of the review period I received the Tannoy Canterbury Gold Reference speakers (review to come) and was able to spend a good deal of time listening to them being powered by the Xs 300.

The elephants in the room

I never start a review by focusing on the downsides, but I’m breaking that rule here. There are three huge elephants in the room when you talk about amps like the Pass Labs Xs 300.

The first “elephant” is price. At $85,000.00 (but yes – for that you get two!) we’re talking money that only the very wealthy can afford. That’s a pretty obvious downside for everyone else.

The second obvious elephant is the sheer size of these amps. Each amp consists of two enclosures connected by an umbilical connector, and one enclosure is 168 pounds while the other is a more modest 130 pounds. I don’t know whether to be proud of the fact that I actually unpacked and set up the Pass Labs Xs 300 completely by myself, or whether to just admit I was stupid for risking injury to myself and the amps by not waiting for help. Visually these amps are anything but subtle. They look great, but they’re definitely not equipment that sits in the background. Visitors definitely will say “Wow – what are those things!?”

The third and final elephant is heat – lots of heat. The Xs 300 are biased to draw 1,000 wpc from the wall outlet constantly. Right now it’s late November in Chicago, and the heat given off by the Xs 300 obviates any need to heat my listening room. In winter this is actually a cost-saving benefit, as well as an audiophile benefit because the sound of our forced-air furnace is nonexistent, but in August the air conditioning literally cannot keep up. By way of comparison, my Electrcompaniet Nemo/Nada combo, which runs in Class A virtually all of the time when amplifying a signal, tends to bring my room temperature up 3-4 degrees during serious extended listening sessions. The Pass Labs Xs 300 can raise my room temperature 5-8 degrees during the same period.

Ok, I’m glad I have that out of the way, because the sonic performance of these amps is fabulous. From a purely sonic standpoint, the only reason you might choose another pair of amps over the Pass Labs Xs 300 is personal taste or system synergy. As you’ll see as we go along, even system synergy isn’t really an issue that affects these amps. Let’s get to it.

Review music

I played a really wide variety of music with my system driven by the Pass Labs Xs 300, but for analytical listening purposes I focused on a handful of tunes:

The Beach Boys – “Wouldn't it be Nice” from Pet Sounds 24/96

Beatles – “Drive My Car” from Rubber Soul 24/44.1

Persuasions – “Angel of Harlem” - from Chesky records, The Ultimate Demonstration Disc 24/96

Soji Yokouchi – “Swingin' On A Camel” from The Super Analog Sound Of the Three Blind Mice

Bela Fleck – “Flight of the Cosmic Hippo”, from Flight of the Cosmic Hippo

Joni Mitchell – “In France They Kiss on Main Street”, from The Hissing of Summer Lawns 24/96

Robert Lucas – “Big Man Mambo” from Luke and the Locomotives

Patricia Barber – “The Moon” from Mythologies

Hot Club of San Francisco – “Mystery Pacific” from Yerba Buena Bounce 24/96

Donald Runnicles/Atlanta Symphony Orchestra and Chorus - “Fortune Plango Vulnera” from Carmina Burana 24/96

Trevor Pinnock - “Concerto No. 2” from The Brandenburg Concertos 1, 2 and 3 by J.S. Bach

The George Enecu Philharmonic Opera – “Concerto No. 5” from Brandenburg Concertos 3 and 5 by J.S. Bach 24/96

52nd Street Blues Project – “You Lied” from Blues &Grass 24/96

Van Morrison – “Astral Weeks” from Astral Weeks 24/96

Relevant equipment for comparisons

My head-to-head comparisons were the Pass Labs Xs 300 against the Electrocompaniet Nada, the Electrocompaniet Nemo, and then against the Nadas and Nemos set up in biamp mode. When I first began biamping the Nemo and the Nada I spent several days going back and forth between (a) using the Nemo for the woofers and the Nada for the midrange and tweeters and (b) substituting the Nada for the woofers and using the Nemo on the mids and highs. This makes a difference because the Nemo and the Nada have somewhat different tonalities.

The Nemo leans a bit to the euphonic side, while the Nada is more neutral, leaning toward but not quite becoming analytical. In the end, I decided to go with the Nemo on the woofers and the Nada on the mids and tweeter, but used silver aftermarket fuses to tweak the Nemos and gold aftermarket fuses to tweak the Nadas to sound slightly closer to each other. This really did the trick for me, and I was able to obtain my desired sound. (Yes, I know – that was a lot of work.) One side effect was to increase my options when doing reviews, since I am able to compare combinations of amps.

In all cases, the amp connections included Walker Audio Eliminator directional antennas. Speaker cables were the Audio Reference Technology (A.R.T.) Super SE and the Silent Source Silver Signatures. Power cords were the A.R.T. Super SE and the Lessloss DFPCs and interconnects to the amps were A.R.T. Super SE, Tara Labs Omega Zero Gold and Silent Source Music Reference in various combinations.

Each side was plugged into its own 20-amp outlet. The two chassis of each Pass Labs Xs 300 monoblock were connected via supplied neutrik connectors, and the monoblocks were place on Walker Audio amp stands.

I also used the Pass Labs XP-20 and XP-30 3-chassis preamps with the Xs 300, with most of my serious listening done using the XP-30. However, I also listened to the Xs 300 in the system without use of a preamp, since the MBL 1620 DAC and Bricasti M-1 DAC (review to come) I had on hand incorporate volume controls. It would have been something to listen to the Xs 300 in conjunction with the Xs Preamp, but it was not to be.

Real power: What’s in a watt?

There’s no denying it – virtually every speaker sounds more dynamic and realistic with higher power amps. Yes, yes – I know that low power triode amp lovers relish the full-bodied and nuanced sound of those amps, but unless their system is perfectly matched to the low power amps they will not come close to the dynamics that great high power amps can exhibit. Based on their “mere” 300 wpc spec, the Pass Labs Xs 300 are not extremely high power amps. I reserve that classification for amps that crack 500 wpc such as Pass Labs’ own X600.5, because I can clearly hear improvements in control, power and dynamics when that additional power is available. However, as you will see, the Xs 300 defies traditional sonic classification.

The Pass Labs Xs 300 is a great example of how the difference between wattage output of various amps can be deceiving. When focusing solely on the characteristics of control, power and dynamics, the Xs 300 sounds more like 600 wpc amps I’ve heard. The Electrocompaniets I run are collectively rated at 1,000 watts per channel, 600 to the bass drivers and 400 to the mids and highs, but the bass of the Xs 300’s, which “only” puts out 300 watts per channel, makes the Vivid Giya G1 deeper, with absolute control.

Subjectively speaking, it sounds like the Xs 300’s go 1/3 of an octave deeper in the bass, while reproducing the full body of the bass with even more control than the Nemo’s. Ry Cooder’s “Flight of the Cosmic Hippo” left my visitors open-mouthed and salivating. I played this tune at least three times to small groups of audiophile listeners with the Xs 300’s doing the amplification, and in each case they all left muttering about how they need to do something about the bass reproduction in their systems.

An amp’s power also affects the dynamic range of the music.

My subjective impression of the Xs 300’s dynamic range is off the charts, especially when paired with the XP-30 preamp. Patricia Barber’s “The Moon” starts quietly, with only Barber and her piano, and still continues quietly when the bass sedately joins in. The laid back opening abruptly ends when the drums explode through the Vivid Giya G1, rapidly followed by an aggressive grunting bass line. Then Barber’s piano joins in, going rapidly to forte and then fortissimo. My system was quite good at startling the listener when the drums come in, but the Xs 300 added more “kick” and made some visitors jump forward in their seats when dynamic recordings were played. I give the Xs 300 extremely high grades for its bass, dynamic range and overall command of the speakers.

Of course, powerful bass which is too analytical or uninvolving doesn’t do us any good. We audiophiles want our bass to sound real – like it sounds live in a good acoustic venue, imparting body to the instruments and exhibiting a natural tonality. In this respect, I have always thought that the Electrocompaniet Nemo, more than any other high power amp I’ve heard, sounds more like a hugely powerful tube amp, but with more bass grunt and grip. That’s why it has been a staple in my system for several years. The Pass Labs Xs 300’s bass is just a tad less full-bodied than that of the Nemo’s, even when it extends deeper. Is it more accurate than the Nemo in this respect? I don’t know if the Nemo’s rendering of the timbre of bass instruments is less accurate, but I do know that it’s like asking how many angels can dance on the head of a pin. The bass performance of the Xs 300 is state-of-the-art in every respect – power, control, extension, transparency, weight, speed, PRATO, dynamics and timbre – and if you prefer another amp’s bass performance it’s purely a matter of personal taste. Paul McCartney’s bass in “Drive My Car” almost sounds like he’s in my listening room – deep, extended, lively and powerful – and only the Nemo has come close to that in the past. The bass of other amps has either been just a tad too thick, too thin, too slow or too analytical to feel really “live”. In my system, the Xs 300 has the most neutral and musically accurate bass of any amp I’ve ever heard.

PrimaLuna DiaLogue Premium HP power amplifier Review

International union–a confluence of four countries for the sake of high-end audio

Question: What do you get when you have Dutch, Chinese, American and Italian joined together?

Answer: Mighty good eating if I’m referring to international cuisine. But since I’m writing about food for the soul, the new PrimaLuna DiaLogue Premium HP power amplifier is the tasty audio dish that I am referencing. PrimaLuna has been a company since 2000, started by the Netherlander Herman van den Dungen who coined the Italian brand name in honor of his grandfather. For the uninitiated, one can get the origin of the company name from the back of any PrimaLuna owner’s manual. To achieve high quality and dependability at reasonable prices, Mr. van den Dungen turned to Chinese manufacturing but with an eagle eye to strict quality control and adherence to design standards.

Operation fail-safe

I’m sure many Dagogo readers are familiar with the PrimaLuna brand, but for those who are not, the company offers audio components which are value-packed with forward thinking safety and convenience features at relatively affordable prices. The new DiaLogue Premium HP power amplifier retails for $3,899.

Much have been written about the various features, either in the high-end audio press or on the PrimaLuna USA website, so rather than rehash the available information I refer readers who are unfamiliar with the company to satiate their curiosity by doing a Google search.

I will, however, mention some of the more important cool safety features. With the DiaLogue Premium HP power amplifier there is a new board for its famed Adaptive Auto-bias (AAB) circuit. Not only does the new AAB monitor and adjust the bias, but it will also indicate which output tube has gone bye-bye when a red LED lights up. Other new items include a larger power transformer, and silver plated Swiss made OCC wiring used in the signal path. Because of the humongous hand wound transformers in the PrimaLuna DiaLogue Premium HP, an installed soft start circuit prevents initial current rush upon turn on from frying them. There is also separate power and output transformer protection circuits to further safeguard what are the most expensive components of the unit. Transformer noise or hum is basically non-existent thanks to its AC Offset Killer circuit. Little or no transformer noise with a tube amplifier is a very good thing! I also didn’t hear any noise with any of the stock tubes.

At the request of Kevin Deal of PrimaLuna USA who wanted me to see the layout, I removed the bottom panel and was happy to see the excellent execution and built quality, not unlike that of a fine automobile. Befitting a premium model, there are premium parts galore and the point-to-point wiring is all neat and tidy. So neat and tidy that I thought the wiring was performed by a machine, but Mr. Deal assured me otherwise. With the PrimaLuna DiaLogue Premium HP, there’s a lot of really nice and expensive stuff one does not usually get with other amplifiers for this amount of money.

With its design philosophy, PrimaLuna has endeavored to minimize the fear of owning tube equipment. While it is still possible for something to go wrong, a faulty capacitor, resistor, or tube for example, the occurrence of a major catastrophe has been reduced to a very low probability. Even solid state or digital components can develop problems, so it is commendable that PrimaLuna have taken steps to make tube equipment that is as trouble free as possible.

More watts, Watson!

The HP stands for High Power or nearly double the watts of the standard DiaLogue Premium power amplifier, depending on the type of tube. With the stock EL34 output tubes, the standard DiaLogue Premium amplifier delivers 25 triode watts and 42 ultralinear watts, while the new HP version bumps up the watts to 42 triode and 72 ultralinear, respectively. 34, 77, 88, 12o, hut, hut! Snap the ball already! You can use any of these output tube types or a combination even, as the famous PrimaLuna photo shows; but I wouldn’t recommend it, unless you want a weird-looking tube complement.

I requested from Kevin Deal a review sample with the black faceplate (also comes in silver) and received one of the first imported units, which was literally fresh off-the-boat.

My review unit arrived with a complement of six 12AU7 tubes and eight EL34 output tubes (four per channel). The tube layout reminded me of chess or checker pieces ready to do battle. In this instance the amp was ready to tackle the musical apexes. The two innermost 12AU7s are input tubes, while the four outer ones are employed as drivers. I asked Kevin why four drivers instead of the usual two and he answered four provides a wider dynamic range. Wider dynamics is always a good thing in my audio book, thus bringing reproduced music closer to the dynamics of a live performance.

I also requested an optional octet of Russian Tung-Sol KT120s to try in place of the stock EL34s, which Kevin sent in a separate package.

This power amplifier is a heavy beast at almost eighty pounds, given my ninety-seven pound, kick-sand-in-the-face frame. For even more power, one can buy two PrimaLuna DiaLogue Premium HP and they become mono-block behemoths, essentially doubling the wattage. While no lightweights to begin with, PrimaLuna gear keeps getting heavier with each new model and in the case of the HP, a beefier power transformer added several more pounds to the standard DiaLogue Premium version.

The DiaLogue Premium HP is outfitted with high quality speaker connectors for 4, 8 and 16 ohm loads, depending on your speakers’ average impedance. To change from stereo to mono operation and double your pleasure, buy another DP HP, then perform the following for both: flick a switch on the back panel; connect an RCA cable to the left input (marked mono) and speaker cable to the right output for 2, 4, or 8 ohm use, again depending on the speaker’s average impedance. The 2, 4, and 8 ohm labels are clearly marked at the bottom of the right output section.

The DiaLogue Premium HP required a fairly long break-in period before reaching full stride. I estimate approximately 100 hours of operation were required before changes in sound came to a screeching halt.

Publisher’s note: This Review was originally submitted for publishing in March, 2014, but somehow was overlooked. With apologies and thanks to Doug Schroeder, the author, for his insightful work and understanding, as well as to Pass Labs which was expecting the Review, we present this article for our readers to enjoy.

Pass Labs X600.5 (Pass Labs XP-20 & X600.5 Review)

When I first approached Pass Labs to conduct a review of the XA160.5 class A monoblock amplifiers I learned that Pass Laboratories, by virtue of influence from Nelson Pass, was a fun-loving, relaxed company to work with. Consider that Nelson was building a wild amplifier at the time entitled, “The Beast with a Thousand JFET’s”. Against that backdrop of casual business atmosphere I met with quite serious components, ones made with slavish attention to detail and particular adroitness in design and build quality. The Pass Labs XP-20 Preamplifier and X600.5 Monoblock Amplifier are examples of the win/win situation created for both the company and the audiophile when refined designs are implemented with outstanding parts. For such reasons, Pass Labs has won a reputation in the audiophile community as gear for serious-minded listeners who do not want to work through permutations of gear in order to set up a fine-sound system.

Nelson does not handle all design at Pass Labs these days, but instead tapped the expertise of engineer Wayne Coburn to handle the design of the XP-Series of preamplifiers. Keeping with the traditional sound of Pass Labs equipment, Wayne and Nelson have made a preamp and amp with an open and airy sound – just what the doctor ordered!

The diseased, or there’s no cure for Ebola

Audiophiles are a sick lot, a bunch of audio-condriacs who sniff at audio systems and scratch their insecurities by collecting “tweaks.” Moping about in a seasonal affective disordered state of the blues, they tumble through ad-hoc systems in search for a cure for disenchantment. While this does not circumscribe the entire demographic of audiophiles, it does encompass a large percentage of them. They return to forums and dealers in droves, seeking a panacea for what ails them – the inability to find contentment with the system they currently own.

I noticed that recently in Guinea a new outbreak of Ebola has surfaced. This is not good, as gruesomely detailed in Richard Preston’s book The Hot Zone. With a kill rate of 90%, this virus is one of the most feared pathogens on the planet. There is no cure for it; the hope is only to contain the hosts, let them die and prevent its propagation. There is, however, a cure for Audiophilia Nervosa and Upgradeitis; the afflicted need to avail them of the proper gear to suit their needs, such as the Pass Labs XP-20 and X600.5, as they may stop the upgrade impulse cold.

Hospital grade

One does not have to be in the audiophile community long before they encounter the phrase, “hospital grade,” particularly in reference to power cords. The designation is supposed to evoke a high standard of construction and supposedly pristine sound quality. If I were to ascribe a general sensation about seeing and using the XP-20 I could do much worse than to call it a hospital grade component. The brushed aluminum casing and washed-out blue LED digits with dual displays for left and right channels evokes images of biological monitors. These are not cuddly kits, but rather cool in a clinical fashion, and they would not appear too out of place next to a centrifuge in a lab.

Pass Labs has been making the X series of preamplifiers since 1998, so a lot of the kinks have been worked out. The XP-20 avoids the absurdity of rows of buttons on the face of the unit, and settles on simple functionality with MUTE, MODE, and INPUT (Left and Right indicated by horizontal arrows) to the left side and a chassis-wide volume dial on the right. A separate, matching power supply unit can be placed either underneath or beside the line stage unit, but don’t try it with the monoblock amps!

The Pass Labs XP-20’s MUTE button removes the signal from the output of the preamp. The MODE button removes the display from the preamp in three increments, “Bright,” “Dim” and “Off.” The default setting, which resets every time the preamp’s power supply is plugged in, is “Bright.” In the “Off” setting the display illuminates as control selections are made for six seconds, then returns to a blank screen. The INPUT select switches toggle through Inputs 1-5.

Input 5 is linked with the PASS THRU (Home Theater) function. It is critical that the gain be reduced to a minimum when first setting the controls for use of the PASS THRU function. Whenever the “Pass Thru” button on the remote is pushed the volume ramps up to 75 in order to prevent serious level mismatches. See the Owner’s Manual for further details.

Savor the medical device-like complexity of the micro-controller, which, “… allows all of the preamplifier functions to be repeatable and accurately controlled.” The digital controls signals are isolated from the signal path and the digital circuits have their own separate power supply from the analogue supply. If the software controlling the preamp ever needs updating, only a socketed microprocessor needs to be changed – safe and secure!

On the Pass Labs XP-20, five inputs are provided, two of which are balanced/XLR and three single ended/RCA. A tape loop with single ended inputs and outputs is provided. The XP-20 has three pair of outputs, all having identical gain structure, one pair balanced and two pair single ended. Though the single ended outputs are paralleled they have low output impedance and high current capability, so more than one output can be used at a time, i.e. one set to the amp for the main speakers and another to powered subwoofers. More durable than a heart replacement valve, the Owner’s Manual states, “The input and output connectors were carefully selected to withstand a lifetime of frequent use.” It’s good to know that the connections on the preamp will still be snug long after the owner’s heart stops pumping!

A couple warnings to ensure healthy use of the Pass Labs XP-20 are in order; the DIN-25 umbilical cable between the power supply and the line stage should never be connected or removed when the power supply unit is plugged into the wall outlet. The power supply has no ON/OFF switch, but rather is powered up when plugged in. Another perhaps overly cautious check is in order upon receiving the preamplifier, that being verification of the unit’s voltage and current rating for local power conditions. A tag on the rear of the unit indicates 240 volts, 220 volts, 120 volts or 100 volts. I have once or twice received a component intended for overseas use having the wrong power supply for the local utility voltage.

Pass Labs X600.5 (Pass Labs XP-20 & X600.5 Review)

Particulars of the X600.5

The Pass Labs X600.5 monoblock amplifier is bold and unencumbered both in aspect and operation. The chunky brushed aluminum façade of the amp matches the front of the XP-20 preamplifier and frames the ubiquitous blue Pass Labs meter as if it were an electronic crèche. The obligatory hospital-sized power button is just below.

The meters always draw attention and are often not understood properly, so I repeat here what I was told about them from my article about the XA160.5: “The meters on our amplifiers are different. They reflect the current consumption of the amplifier, and when the amplifier is operating, they don’t go down to zero like the meters on other amplifiers. This is because the electrical current consumption of our circuits has a fairly high value at all times, a property called the bias. The bias current runs through the amplifiers at a minimum value, determining the class of operation – Class B, Class AB, or Class A.”

Audiophiles can be horridly anal about things like meters, and I’m sure the discovery of the needle on the amp hovering to the side of dead center would be a cause for alarm to some. All it takes to quell fears that the Pass Labs X600.5 is not in operational disease is to scan the images on the Internet, where the needle of the functioning amp is seen most often not centered. So, go ahead and lay that irrational demand for a perfectly vertical needle on the Pass Labs meter to rest.

On the backside are found both an XLR and RCA input, two pairs of output connectors (they accept only spade terminations), a pair of binding post connectors for remote power on, a thermal magnetic breaker switch and a detachable IEC 15A power cord socket.

Built with “Supersymmetry” topology, the X600.5 is said to have, “… a connection between the two halves of the balanced circuit that further perfects the match of common mode artifacts.” A balanced power circuitry scheme might typically achieve a 90% reduction in distortion and noise, but Supersymmetry offers an additional 90% reduction, “… such that it has about 1/100^th of the distortion of a conventionally simple and otherwise identical amplifier.” I take the primary benefit of that extreme design and build quality to be heard in the preternaturally expanded soundstage with a high degree of subtlety as regards the performers and instruments, as will be discussed further.

Regarding warm-up and listening quality

With all this technical prowess Pass Labs opts to keep a lighter tone in its Owner’s Manual. Consider the levity of the comments introducing the topic of component warm up:

“There is an Extremely Small (but Non-zero) Chance That, Through a Process Known as Tunneling, This Product May Spontaneously Disappear from Its Present Location and Reappear at Any Random Place within the Universe, Including Your Neighbor’s Domicile. The Manufacturer Will Not Be Responsible for Any Damages, Inconvenience or Mental Anguish That May Result.

There is a much higher probability that when you first plug your new pre-amps power supply into the wall and listen to your favorite selections that you will not be experiencing the full measure of performance this product is capable of. These are high bias Class A topology circuits and their performance is largely temperature dependent.”

Notice how nothing is said about the impact of warm up upon the condition of Tunneling. This is a serious oversight on part of Pass Labs, and I suggest they conduct research to resolve that question, for surely a few hyper-intuitive listeners will want to know whether a Tunneled amp needs as much warm up!

Electra-Fidelity A3-500 300B monoblock amplifiers

I first met Tony Chipelo at the 2014 California Audio Show. He was sharing a room with Fritz Speakers and it was the best I had heard the Fritz speakers sound at a show. Electra-Fidelity is a boutique high-end audio company in Las Vegas, NV. It was founded by Tony Chipelo in 2010. In addition to other high-end audio products, Electra-Fidelity is the authorized marketing and distribution arm for the electronic circuit designs of Jack Elliano, who is well known as the founder and manufacturer of Electra-Print transformers. Under the Electra-Fidelity brand they market many of Jack’s designs, all of course featuring his very own, hand-wound Electra-Print transformers.

According to Tony the A3-500 amplifiers are the first Electra-Fidelity amplifier to use Jack Elliano’s proprietary Class A3 design with Low IMD circuit. The amplifiers are 300B single ended triode amps. The review amps were supplied with Sovtek 6A3 tubes that are the exact specification and plate size as an original 300B, but using the smaller 6A3 bottle. The driver tubes are either 6ER5. The bias for the A3-500 is preset for the tubes specified for use with the amplifier. In addition, the circuit is a low IMD two-stage amplifier that uses an algebraic summing loop. This lowers IMD, or mixing of low and high frequencies commonly heard with other amplifiers as amplitude distortion present at high music levels. A circuit with a fixed tuning process keeps this loop operating at the optimal level. As such, keeping the tubes near optimum operation is needed to assure top performance.

Design Concepts

Electra-Fidelity list the following as their design concepts.

1. High gain, high transconductance, low plate impedance tube.

2. Algebraic summing loop resistor is used to lower IMD and this single loop will decrease IMD rise with increased level, since this one tube acts as two tubes. 500V on the plate (versus the typical 350V or so for 300B circuit designs). Class A3 zero negative feedback design circuit with specially wound transformers to match. In summary, the Class A3 circuit shifts total plate dissipation, uses higher voltage, and uses lower current, with increased grid drive over maximum output without drive distortion.

3. Plate Dissipation: The voltage is increased over the published rating with a lowering of the published current rating.

4. Load: The impedance remains fairly constant over the bandwidth due to impedance being a different set of rules expressed by the inductance used. The result is less THD and IM distortion (heterodyne) which now appears nearer the peak level and usually not used and heard. The sacrifice of fractional power is much less than if NFB were used to lower distortion and power.

5. Grid Drive: The grid drive signal to power amplifier stage provides an undistorted signal level over the amount needed to clip the power output tube. In other words, the output stage will be at its maximum limit (clipping) before the driver is at its maximum limit. Therefore, the driver must supply current and the bias of output tube must not change with signal levels.

6. Transformers are wound for a single output impedance (4, 8, 16 ohms, etc.). Review sample is 8 ohm.

Now all this is way above my technical understanding but I thought it might be interesting to some of you. So, I’m going to get to the thing that really matters. How does my system sound when powered by these mono blocks?

I have heard so many wonderful things about the products from Pass Labs, that I was very intrigued, to say the least. I have heard from many sources, that their products sound excellent, are very well designed, are beautifully built and that they are extremely reliable. I’ve also heard great things about the company’s main man, Nelson Pass. Things like, he’s an excellent transistor designer, to he is very humble, to he’s a very giving man – he contributes some of his designs and publishes them in public forums. I have also read somewhere, that many feel that he is “one of the best audio designers still living”. This is very high praise for both the Pass Labs products, as well as the founder, Nelson Pass. The facts seem to support these statements, as Nelson has received several patents for his circuit and amplifier designs. He has designed products for Threshold, for other companies like Nakamichi, well as starting Pass Labs, many years ago.

I know two audiophiles in Toronto that have Pass Labs equipment and both of these people, just love their amplifiers and preamps. Up until the time that I received these monoblocks for review, I have not really had very much experience with Pass Labs products. I’ve heard them here and there, at a dealer here in Toronto, and also at a couple of audio shows, but I haven’t really heard any Pass Labs equipment for longer than about 5 to 10 minutes. The systems that I did hear them in for brief periods of time, sounded very good.

So like I said, I was very intrigued about Pass Labs enough, that I called our esteemed publisher and asked if I can review the X260.5 monoblock amplifiers. I have been using monoblock amplifiers for several years now, and I prefer their lower noise floor, better isolation, and the fact that, with monoblocks, you can place the amps closer to the speakers, therefore reducing the length of the speaker cables between the amplifier and speaker. So after speaking with Constantine, in a very short period of time I received a pair of these monoblocks, and I put them through their paces.

When I received the Pass Labs X260.5 monoblocks, I noticed that they were packaged very well and I received them in excellent condition. When I took them out of the box, I started to admire the amplifiers’ sheer beauty. They looked very well put together, the chassis was sturdy and strong (heavy as well), and aesthetically, they also were very pleasing to the eye. The front panel was silver in color, looked like it was made from aluminum and it was very thick. In the center of this front panel, there was a rather large-ish power meter which was backlit in soft blue lighting, very elegant indeed. Just below this meter, is an ON-OFF switch, which switches the amplifier on from stand-by mode. The thickness of the front panel was also larger than most products that I have seen and have come across. It is also very elaborate and is machined very well. All this gave me a feeling of “pride of ownership”. To the left and right side of the chassis are the heatsink fins. The fins extend outwards and upwards from the center of the amp, at roughly a 45° angle, which is a nice aesthetic change from the more traditional vertical fins that extend outward at 90° from the chassis.

The rear panel is very well laid out. Towards the bottom there is an 15-amp IEC receptacle, as well as the master on-off power switch. There is also a 12V trigger for automatically turning the amp on. Two sets of binding post are available for the people that bi-wire their loudspeakers. Personally I am a mono-wire type of guy. Towards the bottom of the panel, there is a fuse-holder which allows one to change the fuse without opening up the inside of the chassis, a very convenient and useful feature, if the fuse ever blows. A very unusual item was a ground post, which is very unique in a power amplifier. I also noticed that the rubber feet at the bottom of the chassis were rather large, having a large diameter and taller than most rubber feet that I see on power amplifiers.

There are no carrying handles on the front panel, but there are two on the rear panel. I thought this was a great design choice, due to the fact that the front panel looks very elegant without the handles, yet there are handles at the rear panel which makes it extremely easy to move this rather heavy amplifier around. It is also easier to remove the amplifier out of the box, as a result of these handles.

Both RCA, as well as XLR inputs, are accommodated at the rear panel. One of the exceptionally nice things about these XLR and RCA inputs is that there is no toggle-switch there, to switch between the RCA and XLR connectors. I believe this is a great benefit, because it eliminates one switch from the circuit, the part of the circuit which is at the very input of the amplifier. One of the worst places you can put it in. If you have done as much modifying of equipment as I have, you soon realize that you can hear a switch in the circuit very easily. Just like you can hear the difference between different input connectors, binding posts, different wires, even different solders. Most switches, even in high-quality high-priced equipment are vastly inferior. It is really great that Pass Labs has figured a way to switch from the XLR to the RCA inputs without the need of such a switch. Very impressive. A unique feature of the XLR is that, if you choose to use the RCA input, you have to put a U-shaped jumper in the XLR input socket. If you use the XLR input, as I do, you need do nothing other than to simply plug the XLR connector in the socket. This review was done with the XLR balanced connection exclusively.

The Pass Labs X260.5 amplifier produces 260 watts into 8 ohms and 520 watts into 4 ohms, with the first 5 watts being in Class A. The amplifier produces 26 dB of gain. If you go on the Pass Labs website, you will see that the model X260.5 is part of what they call the .5 series. In addition to the .5 series, there are also the newer .8 series, both are available at this time. The amplifier is built using JFET transistors for the front end, and MOSFET at the output stage. The amplifier runs hot at the heatsinks, not overly hot mind you, but it does run hot. If you put your fingers on the cooling fins, you can leave them there for approximately 3 to 6 seconds, before having to move your fingers.

I removed the top cover to see the interior of the Pass Labs X260.5 amplifier. The first thing I noticed, is that there was very little wiring throughout the amplifier and what wiring there was, was short in length. The wires were connected to the circuit boards using solder in all the connections that I noticed. This is excellent. Most manufacturers use these cheap tin/steel “push-on” connectors, which make a terrible connection and sound like garbage. Yes, I have experimented and the push-on connectors do sound like that. And these cheap connectors are used in even very high-priced audio equipment. This, to me, is inexcusable. Way to go Pass Labs, for not using them.

At the front of the Pass Labs X260.5, there is a good sized toroidal transformer. Most amplifiers usually have a few large storage capacitors in their power supply. In this amp, there are smaller capacitors, but there are many of them. The circuit boards are located towards the rear of the amplifier, right next to the rear panel and the input and output connectors. Overall, the construction is top-notch, the amplifier is extremely well-made. The circuit boards were also very well laid out and very neatly built. True to what I’ve heard about Pass Labs products, these amplifiers worked perfectly, with no muss, no fuss, and no surprises. Just like the Pass Labs literature states, “They also possess greater reliability. These amplifiers are harder to break and easier to repair, if they ever do.”

To illustrate how durable these amps are, let me give you an example. Now this procedure is something that, I do not recommend that you do. The Pass Labs X260.5’s are so well-made and well-designed that when I removed or inserted my XLR interconnect cable into the XLR input, while the amp was on, I heard nothing, there were no clicks, no thuds, nothing, silent as a tomb. In view of all the above, it sure felt like these amplifiers are well-designed, well-made, and felt like they were bulletproof.

Pass Labs XA30.8 Review, Part II: “Driving the Quad ESL”

I shared in Part I of the Pass Labs XA30.8 review that the reason for getting the stereo amplifier in was because I knew I had a pair of Wayne Picquet’s restored Quad ESL (the 57) coming in to listen to. So I was trying to figure out what amp I wanted to use with them. Years ago, when I owned these legendary speakers my two favorite amps to use with them were the Bedini 25/25 and even better, the original 25-watt Electrocompaniet; two Class A transistor amps. I was not able to find anyone who had either of these two to spare, so I begin to look for a current production amp that was a low-wattage Class A amp.

One of the things that you need to know about the original Quad ESL is that they are inefficient, have an almost impossible impedance curve to drive and can only handle about 30 watts without the panels being harmed. In my past experience tube amps, even Quad’s own amplifiers just can’t keep the mid-bass from getting out of control. So theses requirements left me with fewer choices than I had expected. The amp I settled on after much research was the Pass Labs XA30.8, so I requested one for review and the people at Pass Labs were nice enough to send me one.

So, I went over to my college audio-bud Ken Askew and picked up the Quad ESL as restored by Wayne Picquet. I should stop and thank Ken for making it possible for me to relive some really special audio memories. I had not had a pair of original Quad ESL in any of my listening rooms in a little over 30 years. So, the big question was would they sound as good as I remembered or had they become better and better in my mind over the years?

If you’re not familiar with the original Quad ESL, the patents were issued in 1954 and the first pair was sold in 1957. This is why they are sometimes called Quad 54 or 57, but that was never their name or model number. The ESL was the world´s first full-range electrostatic loudspeaker. In the 25 years of its production, 60,000 Quads were sold. The design was radical, incorporating panels sandwiching an ultra-thin sheet of PET film. They are 31 inches tall, 35.5 inches wide and10.5 inches wide at the bottom where the transformer and power supply are located. The electrostatic panels themselves are slightly curved, covered with metal mesh on each side and about 1.5 inches deep. The metal covers most often are black or bronze colored, but I have seen a rare pair of white and silver.

I listened to the Quads with four different amps: the Pass Labs XA30.8, the 47 Labs 4733 Midnight Blue Integrated Amp, the original Quad II mono blocks and the reissued Quad II mono blocks. I’ll talk about each of these in my Beatnik column of the Quads, but let me say that the XA30.8 was the hands down winner.

So, where was the XA30.8 better than those other amps? Well let’s start with the fact that the speakers sounded more powerful with it driving them. Yes, they seemed to play a little louder with the Pass Labs XA30.8 but this sense of power was there even at very low volumes. The next area where it was the better amp was in the bass. The Picquet Quads with all the amps had better bass than I remember my single Quads having, but with the XA30.8 they had better and more powerful bass than I remember even my stacked Quads having. They still won’t play as loud as a stacked Quad setup though. The bass on the Quads with the XA30.8 was deeper, revealed more air around and within bass instruments, was tighter than either of the tube amps.

The Pass Labs XA30.8 also walked away when it came to the way the Quads produced a correct soundstage. I surely never remember the Quads producing this kind of soundstage. It was room filling, wide and very deep. The way the Quads float an image in space is magical and this was far better with the XA30.8 than any of the other amps.

Voices are the forte of the original Quad ESL and again they sounded the most tonally correct with the XA30.8. This combination was truly lifelike on voices, both male and female. The midrange of the Quads with this amp was exceptional as long as you are happy with a mid-hall prospective; this is the prospective of the Quads not the XA30.8 which doesn’t sound mid-hall in the least with my Teresonic Ingenium XR Silver.

Violins, flutes, piccolos and cymbals all sounded very musical with the Pass Labs XA30.8 on the Quad. They never sounded strained or strident, but very sweet, natural and full of air. The top end was extended, open, airy and as I have mentioned in part one of this review it was well controlled. This top end is partially responsible for the fine detail and the tightly focused spatial presentation my system portrayed with this amp-speaker combination.

Specific Examples

Let’s start with Ella and Louis, on cut 2, “Isn’t This a Lovely Day,” this combo let me hear the beauty and lushness of Ella’s voice and the gravely sound of Satchmo’s voice. The voices sounded very alive and his trumpet had nice bite without ever getting out of control. This is the kind of music that the Quads are made for, and while in my system I listened to the whole album more than once. This was one of the albums where the original Quad II amps came close to the Pass Labs, but the XA30.8 held the bass line together better and had better PRaT than with the Quad IIs.

Elvis is Back is the album that has Elvis’ version of “Fever” on it. This is a cut you would think is not ideal for a single pair of Quad ESL. If you’re listening most of all for slam, tightness and power, then you are right. If instead your are listening for emotion, timbre and the feelings Elvis is trying to convey, then this combo is very good. Quad ESLs are never going to give you the slam many of us equate with this LP regardless of what amp you use, but the combo of the Pass Labs XA30.8 and the Quads really sounded great on this cut and on the rest of the LP. I had never heard the disk sound better.

In 1986, North Star Record release a recording of Arturo Delmoni playing the violin called, Songs My Mother Taught Me. I remember vividly the first time I heard this album. It was at a Dr. Norton’s house in Auburn, Alabama. On his Futterman amps driving a pair of Quad 63, I was simply blown away by the beauty of the violin and piano. Twenty-seven years later I acquired that very LP thanks to a friend in Auburn. Let me tell you this is another LP that lets you hear what Quads are all about and especially the original ESL. This LP sounded great on all four aforementioned amps, but the fullness without overhang that the Pass Labs XA30.8 played with was hands down the winner. The sound was organic, smooth, quick and the violin just floated in a cushion of air behind and above the speakers.

Conclusion

If you want to read more about the sound of the original Quad ESL and about the two versions of the Quad II mono blocks, keep a watch out for my upcoming review of the speakers that will cover these in more detail. To conclude this part of the review, of the many who can afford it like the ASR Emitter amp on the Quad ESLs, they cost nearly five time more than a Pass Labs XA30.8. No, I didn’t have the Quads when I reviewed the ASR Emitter but considering that I prefer the Pass Labs on my Teresonics leads me to think the Pass Labs XA30.8 should be as good or better and it surely is the better bargain. This amp and a pair of Wayne’s Quad ESL can be yours for around $10k. That’s amazing!

Shortly, there will be a third and final conclusion of this review. Part III will return to the sound of these amps in my reference system. There are some things I have learned with time that I feel I must share. Stay tuned!

Kingsound KS-H3 electrostatic over-the-head headphones

The gushing regarding “all that” headphones is at a fever pitch lately, I thought as I read Arnie Nudell’s review of the Audeze LCD-X Headphones, wherein he said the LCD-X could compete with all of the very best high-end loudspeakers. By that he summarized the headphones had below 20Hz to beyond 20kHz response, very low distortion, and produced sound which seemed to be cut from a single cloth. As I had already embarked on this review and regaled in the experience of hearing the Kingsound KS-H3 headphones and M-20 headphone amplifier, my reaction was, “So what? The Kingsound headphones do that!”

I thought it would be dandy to compare the Audeze LCD-X to the Kingsound KS-H3, and though that did not transpire, I was able to secure the next best thing, the Audeze LCD-3, for a direct comparison to the Kingsound combo, which will be discussed shortly.

But first, some background

The Kingsound M-20 is an OTL (output transformerless) tube amplifier specifically designed to drive the low impedance KS-H3 electrostatic headphones. The fixed cable from the phones to the amp has the five pin configuration known to STAX headphones. A headphone extension cable that works with the Kingsound KS-H3 with either copper or silver OFC is available from STAX.

The form factor of the M-20 amp reminds me of the slim chassis Marantz or Krell amps, except for the removable black wire cage atop the Kingsound amplifier. The brushed aluminum faceplate features a solitary black VOLUME dial, and the headphone jack. At the rear resides the 15A IEC socket with the expected fuse compartment, the illuminated ON/OFF rocker switch and the L/R RCA outputs.

The tube complement is, from front to rear, a pair of 12Ax7, a pair of 6BQ5, and a single rectifier 6V6 to control the bias voltage. Upgrade tube sets are available, and my understanding is that the most rewarding tube to change is the rectifier. Feedback on message boards suggest the Gold Lion brand is worthwhile, but I would explore other brands as well, as I have found there to be no direct correlation between tube brands and an audiophile’s preferences.

Further, you will want to get to the really good stuff by reading my upcoming experiences with discrete opamp rolling the Eastern Electric Minimax DSD DAC Supreme. Tube rollings are child’s play in comparison to the benefit of swapping discrete opamps. If you jack up the performance of the DAC, the headphone amp goes along for the ride. For less than the price of the set of Gold Lion tubes one can secure a set of discrete opamps from Burson, DEXA or newcomer Sparkos Labs. For twice the price of the tubes you can secure all three brands of discrete opamps and leverage their strengths to customize the DAC. The Eastern Electric is not the only DAC to benefit from these products. For serious listeners this should be a mandatory upgrade for DACs with socketed opamps. If you get all three sets you can tune the headphone experience exquisitely, having many options as opposed to one with a set of tubes. This is something you will be very happy you explored.

Wearing the KS-H3

As with the review of the Kingsound King III ESL once again I need to address an anomaly, albeit this time one of seemingly less importance than the construction of the speaker. Kingsound has labeled the headphones “KS-H3” and every reviewer I’ve seen work with them has referred to them as such, but the headphones themselves are labeled “H-03”. Kingsound at times moves fluidly with changes to products and at other times renames products readily.

Putting on the Kingsound KS-H3 headphones, the soft rim of the ear cup assembly felt so large as to be encroaching upon my eye. It felt enormous, cavernous for headphones. In an age when earbuds are a man-on-the-move’s best friend, this was like being placed in a symphony hall, my ears calling out to the boundaries of the headphones, “Helllloooooo,” and the cavity responding, “Whaaaat?” It’s an auditory wide-open-spaces enclosure blissfully free of some major annoyances of headphones – the tight fit atop the head, the pressure against the ear, the smothering eardrum feel. For all the size of the KS-H3 it is worn lightly, not quite a light as air fit, but pretty doggone close!

Then again, I have said many times that ear buds are the equivalent of placing a sonic jackhammer into the ear. Imagine how a laser is focusing light such that it can be amplified and the appropriate wavelength chosen and focused to cut steel! Now, consider the headphone, directing a myriad of frequencies with laser-like precision directly at the tympanum. Nah, not my idea of a great way to extend hearing into my golden ears. I know it is the listening level that makes the critical difference, but I simply prefer the feel of a phone to a bud.

Did I mention the soft earpieces of the Kingsound KS-H3: They sit so lightly about the ear and are so smooth to the touch that an hour and a half later they don’t feel irritating at all? In a warm room they do trap some body heat from the skin and it feels a tad tropical inside the ear cup ecosphere. It could be less comfortable to wear them three or four hours for that reason, however, shorter listening sessions present no annoyance. The isolated headband lifts the set well off the head such that there is no stress felt upon the skull. In terms of the lightness and softness of its fit, the KS-H3 outperforms the bulk of higher end headphones on the market.

The Kingsound KS-H3 is finished with an attractive aluminum perforated shell that has a thin red band running along its circumference. The cable is fixed; no upgrades are possible to this wiring as it is designed to be used only with the M-20 amp. The philosophy is somewhat akin to active speakers; no choice, no muss, no fuss. While flexibility in pairing other amps and cables might be desirable, it is not desirable to have a mismatch between the outputs of a headphone amp attempting to drive a pair of ESL headphones. Kingsound worked from the premise that a custom amp best suited for the phones would be an appropriate solution. Given the performance of the pairing it is hard to question that philosophy.

The M-20’s appearance seems to straddle the best aspects of vintage and contemporary amp design. The elongated rectangular chassis sits low, and its narrow footprint carries a sensibility of space ergonomics. The top perforated metal tube protector cage can be removed by slightly squeezing the sides of the cage. The black, featureless volume control knob free from detents operates smoothly. To the right, is the proprietary jack for the headphones with a symbol of a headset over it.

On the back of the amp is the single set of sturdy gold plated RCA input jacks, an illuminated rocker ON/OFF switch, and the receptacle for the 15A IEC power cord. I like the illuminated power switch as instantly I can tell when making signal connections whether the unit is off. I wish more audiophile component companies would follow suit, as middle aged eyes get tired of straining in dimly lit corners to spy small “O” and “-“ symbols on buttons.