INTRODUCTION

INTERNAL LINKS

For many years, if not decades, power amplifiers were one of the single biggest (component) disappointments. In fact, they had even more serious compromises than preamplifiers. While there were a lot of "good" amplifiers, few were "excellent" and even fewer were "superb". As for "great", I would have passed on naming even one amplifier until recently. However, there are finally a few amplifiers, auditioned in the last few years, that appear to have earned that accolade.

The standards here are higher than others, and this is why you will find only 2 or 3 amplifiers in Class A, not the 50 or more you will find in Stereophile, because "Greatness", even when loosely defined, is never that common in any human endeavor.

I would read this section more carefully than any other, because there are more conditions, caveats and warnings than in any other component category. The only good news about amplifiers is that almost all of the best models we’ve heard are under $10,000.

This is the one category where "big money" rarely buys you better sound, regardless of what you’ve read elsewhere. In fact, just the opposite is almost always true. There is very good reason for this...

You will not find even one megabuck (over $ 20,000), super-power amplifier listed here, either solid-state or tube. Why?

None of them, regardless of their engineering, execution or reputation, can approach the sound quality of the good low-power amplifiers. The all have signal paths that are far too complex to preserve the subtleties and essence of music, particularly acoustical, but even electronic. They only excel in brute force dynamics, outer detail, soundstage size and low-end control with speakers of inferior design.

With these amplifiers, you are paying (a lot) more for lower quality sonics, and that is one reason why you will inevitably see them for sale at a fraction of their retail price within months of being sold. The other reason is that the manufacturer's markup on these ultra expensive amplifiers is usually much higher than on other amplifiers. Why?

The manufacturers and distributors have realized that "prestige", based on an artificially high price, is much more important to the prospective purchasers of these components than the actual sonic performance. (Loudspeaker manufacturers and distributors had learned this same "lesson" years earlier.)

(For more on the subject of: The inevitable sonic problems of "components with excessive size and complexity", please go to My Audio Philosophy.)

A reader recently sent me an email, with a question other readers have also asked or inferred, either directly or indirectly. Here it is:

"I can intuitively grasp why higher efficiency in a loudspeakers would be a plus. I do not understand why (minimum 6 ohms everywhere) is mandatory to achieve minimalism. Why would loudspeakers (93 db) with lower impedances and first order crossovers violate fundamental principles?"

My Reply- The speaker's impedance ("load") is almost as important as its sensitivity, maybe even more so in some cases.

This is because a speaker with a low impedance, even if it's only at particular frequencies, will usually cause a single-ended-triode (SET) amplifier to either noticeably distort, or even entirely clip. These amplifiers rarely have the current reserves required for such a low impedance load.

If that wasn't bad enough, even if/when the amplifier is not distorting, its frequency response will look like a "mountain range" with a speaker which has a varying impedance. All of these problems are very audible, and they are why some audiophiles feel that all SET models are for "fools", or for the (figuratively) deaf.

I've had direct experience with this problem on several occasions. My prime example: The Wilson WATTS are pretty sensitive compared to most other speakers, but they have/had dramatic impedance dips at certain frequencies, causing all the single-ended amps I had, even those with 20 watts or more of power, to distort. It was this speaker, more than any other, that proved to me that sensitivity was only half the solution. I wish it were otherwise, but it isn't. I ended up building my own custom crossover for my WATTS. It was the only certain method to eliminate the problem.

I believe an easy speaker "load", both in sensitivity and impedance, is the key to putting together a truly great audio system, so all serious audiophiles will eventually have to tackle this issue.

I recently received a depressing letter from a reader who purchased a VTL Ultimate* preamplifier, on my advice and recommendation, only to see it break down after a few months, with the required repairs too expensive to be economical, at least for this reader, who is in the tube elctronics business no less. So readers, please...

When you are buying an audio component used, especially an older tube unit from an unknown source, make certain there is some previous "feedback" or some resource if there are problems. Either that, or make sure the price you pay is low enough to allow you to still spend something to bring it up to top "stock" performance. (Modifications can come later.) Ideally, you should hear the component in your own system, and check it out personally, BEFORE the purchase. Fortunately, the nightmare this upset reader experienced is relatively rare, at least in our audio world, but always be careful before you make your commitment.

*This preamplifier is generally reliable, so I'm not trying to make an "example" out of it, but the reader informed me that the (VTL) factory won't be of any help (with schematics or parts lists), so be extra careful with it.

I've now listened to these amplifiers long enough, and in a revealing enough manner, to come to a confident assessment about them: This is the finest high-power amplifier I've ever heard. I've already mentioned their superb bass reproduction (see below), and now I've also heard them on the Ars Acoustica satellite, from around 100 Hz and above. That listening session (and another) was relatively short because of a component mismatch, as will be explained below, but long enough for our purposes. Overall, we (my associates and I) have experienced a combination of strengths we've never heard before.

These amplifiers possess three areas of pre-eminence, and one of them is unprecedented in our experience:

1. The dynamic contrasts, shifts and intensity are in a class by themselves. It is the first amplifier I've ever heard that allows a good dynamic speaker to display an intensity (startle, goosebump and shock capability) which is reminiscent of a good horn speaker. Every other amplifier I've heard in my life is compressed, to some degree, in comparison with the Dragon. Certain transients actually sound like their "shot out of a cannon".
2. It has a huge soundstage, maybe the largest I've ever heard, but I've heard nothing larger than it.
3. It is very immediate. More so than any high-powered tube amplifiers I've ever heard, and only equalled by the finest SET amplifiers or rare transistor models.

It is also very neutral, but if you're hoping it can also equal the finest low-powered SET amplifiers, such as the Coincident Frankenstein or the Golden Tube 300B, in their unique strengths of ultimate purity, transparency and an ultra-low sound-floor, I must sadly dash that hope. Just as it took only a few minutes (or less) to hear the Dragon's obvious strengths (above), going back to the finest SET amps I know quickly confirmed that there is still a noticeable comparative "gap" with the Dragon's reproduction of the most subtle elements of music. I will go into more detail about the Dragon's performance, but a very rare problem, which is inherent in the design of my ultra-minimalist system, has prevented me at this time. Let me explain...

Because my preamplifier, the Jadis JP-80, has been gutted (there's no line stage or even a cathode follower), and effectively turned into a dedicated phono stage, it no longer has the capability of driving an amplifier (full-range) with an input impedance of less than around 200K ohms. (The Altec 1570B input impedance was over 300K.) Since the Dragon has an input impedance of 60K ohms, this means I'm not able to drive my speakers full-range at the current time. (An impedance buffer and crossover assist the JP-80/Dragon interface when it's driving only the subwoofer.) So I intend to change the Dragon's input impedance to 250K this Summer. I'll then be able to hear it full-range, on both the Ars Acoustica System Max and the Coincident Victory II.

Meanwhile, I have already extensively heard the Dragons on my subwoofers. Here's the essay I wrote about these experiences. I feel it is still relevant.

These are the finest amplifiers I've had on my Ars Acoustica System Max Subwoofers. I can not state that they are superior in every single sonic parameter, but they are definitely the best overall. In most instances, such a high level of bass performance would be wasted on a single octave (20 to 40 Hz), but in my case the "subwoofers" go up to around 160 Hz, which is three entire octaves, and thus highly critical to the ultimate sonics of my system.

While I have no present intention of designating an amplifier as a Reference strictly on its bass frequencies (though maybe that's something which should be further thought out in the future), I would like to take this opportunity to discuss my past experiences with the Ars Subwoofers, and the most interesting amplifiers I've used with them. This should be relevant to a wide audience of audiophiles, because it deals with bass reproduction in general. I also would like to post my thoughts and experiences on the utilization of subwoofers, which I've now used in my various systems for almost 30 years. This will all be necessary to set the stage and to put things in perspective.

I've had the Ars Acoustica speakers for almost 10 years now, and I've tried countless amplifiers on them, on both the satellites and the subwoofers, and sometimes even one amplifier driving them full-range. This was easy and convenient for me, because I had my audio store in the same building in which I lived between 1996 to 2001. At this time, I'm only focusing on my most interesting experiences with the System Max subwoofers.

The first amplifier I used on the Ars subs was the Parasound HCA-2200; one pair of them switched into mono operation. The Parasounds were superb bass amplifiers, especially for the money, though they couldn't operate into a really low impedance load in mono. Since the Ars is almost exactly 4 ohms, and very flat, this was not a problem. I had originally picked up the Parasounds for my previous woofer system, the Tympani IV bass panels (in heavy granite frames), which required huge power (500 watts minimum) and control, though they had no real response below 30 Hz, so they weren't a true "subwoofer". I also had the ultra-rare Concentric Speaker "Super-subs" (which I still have, and will discuss later).

I was very happy with the Parasounds, but after a lot of experimenting with a number of amplifiers (now mainly forgotten), I eventually replaced them with a pair of Atma-sphere M-60 Mk. II OTL amplifiers. This was a surprise to me, considering the relatively low impedance of the Ars sub. The Atma-sphere didn't have nearly the power of the Parasounds of course, but they went just as low, were just as controlled, and they passed through more musical information in a natural manner. In effect, I traded some quantity for some quality. This brings us to around the year 2000. Two more amplifiers, both of them using (Direct Heated Triode) tubes, then entered my audio life.

The next amplifier I used, the Altec 1570B, with heavy modifications designed by Tom Tutay, ended up being my long-term choice (6 years), though it was actually my second favorite. The Altec sounded very similar to the Atma-sphere, but it had more power. It was, in the end, in my room and system, a combination of the best qualities of both the Atma-sphere and the Parasound. Just when I thought I had found my "final" subwoofer amp, another contender arrived out of the blue (literally, since it was metallic blue). This was the Viva Aurora 572 amplifier, imported from Italy, which was also visually stunning.

The Aurora was an expensive amplifier, the most expensive by far I had ever owned, but I was able to get a "super deal" on them. I was lucky, Viva was just then changing this model, converting it from the "obsolete" 572 output tube to an 845 output tube. I first played the amplifier in my store, comparing it to every serious amplifier I had, and could find. It didn't take long to appreciate its outstanding performance. In fact, it proved to be noticeably superior to all of the other amplifiers. It was especially impressive on the Coincident Super Eclipse, even startling highly critical listeners who had never liked that speaker in the past. After this encouraging experience, I decided to put it in my own system, which was the toughest and most revealing test I had, or knew.

I still remember one of my associates and I, plus a helpful and enthusiastic customer, bringing the Viva Aurora 572 amplifiers into my personal listening room. We were all excited, because we had just heard the Vivas easily outperform the finest amplifiers I had in the store. This time, we were going to compare it with my (highly modified) Golden Tube 300B amplifiers. The Golden Tube 300Bs only drove the satellites of the Ars Acoustica System Max, while the (modified) Altec 1570B amps drove the Ars subwoofers.

It didn't take long to hook up the Vivas, and then warm them back up, while also resetting the subwoofer sensitivity. The Auroras sounded superb. We played a variety of music, all records, until we felt familiar enough with their sonics to go back to the Golden Tubes. The only surprise at that stage, for me anyway, was that the Vivas had only a very slight advantage during the loud passages. I was expecting something much more noticeable in that area.

We then warmed up the Golden Tubes with different records, and after 30 minutes or so, we started playing the same records we had heard with the Vivas. We heard the differences almost immediately, and they were obvious to all of us. As good as the Vivas were, the Golden Tube amplifiers, in comparison, were in another sonic league. They were so natural and pure, while lacking any type of electronic signature, that it felt like nothing was even in the system to describe. In simple terms: It was almost as if they had an infinitely low "sound-floor".

We all had different reactions: I was disappointed, while my associate told me he wasn't surprised at the results, but had kept quiet to avoid influencing us. Meanwhile, the customer was so shocked by what he had heard, that he could hardly speak. He looked closely at the Golden Tube 300Bs, which appeared to be put together with spare parts in someone's garage, and couldn't understand how it could perform at such a high level. I carefully explained the simplicity of the Golden Tube's circuit, and the modifications that had been made. Still, I'm not sure I totally convinced him that it was all "science". Then, wanting to complete the picture, I asked my two assistants to help me with one final experiment; replacing the Altecs with the Vivas on the Ars subwoofers. The results: Paydirt!

The sonic differences between the Altecs and the Vivas were easily noticeable, though subtle at times. The Altec had a little more power and drive, while the Viva was more natural and pure, and also had a little more detail. However, most importantly to me, the Viva had a lower sound-floor. This, in turn, lowered the entire system's sound-floor. It was another "quantity versus quality" choice, and once again I chose "quality". My system had never sounded so natural, and "disappeared" as well. Unfortunately, I only had this combination for a month or so. I soon left Toronto for Florida as planned. I felt that the Vivas were somewhat of a luxury at that precarious moment of my life, so I sold them to a lucky customer. Around 9 months later, now in Florida, the modified Altecs went back into my new system, and that's where they've been for most of the last 4+ years, until now...

I've had the Coincident Dragon amplifiers in my system for around a month now. I would have written my report earlier, considering it's only bass frequencies being discussed here, but I've also changed my turntable set-up (VTF), plus there's been some (final hurricane related) construction work on my house which caused even further delays. This is all in addition to the normal tube amplifier break-in process, since I received the pair virtually brand new. Let's start with a short physical description of the Dragon amplifier.

It's a push-pull design, using (two) 211 DHT output tubes, with a 6EM7 input tube and a single 300B as a driver (there are no tube rectifiers). I'm using a Svetlana 300B for now, and the 211s are NOS GE. Israel Blume, who created the basic design of the Dragon, claims that this output tube is critical to attain the amplifier's ultimate performance, though they are costly. It has an accessible volume control on the top plate. This amplifier is very well built, with an industrial, heavy-duty "no-nonsense" appearance. It is rated at around 80 watts per channel and weighs around 50 lbs.

It requires absolutely no biasing, which is a serious advantage considering that the output tubes have 1,200 volts on their plates. There is one downside from the high voltage though, the amps do get quite hot, and are painful to touch after they're on more than two hours or so. I looked inside, which I don't recommend to others, and can testify that I couldn't find even one modification opportunity. This is the first stock tube amplifier I have ever known where I could make such a claim. (Since this was written, I now think that the volume control can be improved.)

Compared to the Altec/Tutay 1570B, the largest differences I heard, which anyone can hear, are as follows:
1. The Dragons are quite a bit less sensitive (maybe 6 dB or so), because it has fewer gain stages.
2. The Dragons reach noticeably deeper into the lowest bass frequencies (below 40 Hz)*.
3. The Dragons are purer and have a lower sound-floor.

The Dragons were also better in other areas, though to a more subtle degree; control or tightness, mid-bass impact and drive, and superior retrieval of detail. I can't think of a single area where the Altecs exceeded the performance of the Dragons in the bass, though I don't want to give the impression that there was a "night and day" difference between them. The Altec 1570B is simply too good an amplifier to allow such an extreme expression to be used honestly.

*This made it extra difficult for me to balance the subwoofer with the satellites, since the subwoofer's own balance was now different. I didn't hear this specific problem with the Altecs in my Toronto listening room, because the room itself rolled off the deepest bass frequencies.

The only question still in my mind is something I have no chance of answering: How does the Dragon's sound-floor compare to the Viva Aurora 572's? I have a strong feeling that they're very close, based on my similar gut reactions when first hearing both of them compared to the exact same amplifier. Still, 5+ years is just too long to remember something subtle like this definitively. The only statement I can make with confidence is that they're both "in the same ballpark".

The Coincident Dragon is as good as any other bass amplifier I've ever used in every area of bass performance. This may not be relevant to the vast majority of audiophiles, but it's still important to know, because we're talking about 3 octaves of music. Whether having this level of bass performance is worth $ 9,000 is a personal choice, but I know nothing that equals it for less money. The main qualification of the above claim is the Ars Acoustica Subwoofer itself. Keep in mind that this is the only subwoofer I've used so far with the Dragons, so a short description of the Ars Acoustica is in order.

The Ars is the most revealing (sub)woofer I've ever heard, overall, in this frequency range (20 to 150 Hz). It is made out of a dead (casted) metapolymer cabinet, with three 8" woofers. It is natural, clean, highly detailed and has a very low sound-floor. However, other subwoofers I've heard have greater weight and impact. Its "load" on the amplifier is slightly easier than average. Its sensitivity is around 92 dB/1 watt, while its impedance is a low, though flat, 4 ohms. It will take time, and other audiophiles' experiments, to learn how the Coincident Dragon deals with truly difficult loads, especially those speakers with really low and varying impedances.

Finally, to be frank, I seriously looked for some good reason why the Dragon should NOT be in Class A. I couldn't find any. This search for a "reason" was partly because of the now unusual result; Two separate amplifiers, from the same company, both being in Class A at the same time. This has never happened before. I realize it looks "suspicious", especially since the owner of Coincident, Israel Blume, is a close friend of mine. However, if I didn't report and objectively evaluate what I (and three of my associates) have heard, I would be doing both the readers of this website, and Blume, a disservice. Time will tell whether my judgement about this amplifier is correct, or not.

This is, without a doubt, the finest amplifier, overall, I have ever heard. Three of my associates have also heard this amplifier, in my system, and agree with this opinion and evaluation. Since my former "reference" amplifier, the (highly modified) Golden Tube 300B (now in Class B Upper), has previously survived every challenge since 1996, I feel the Frankenstein must receive an extensive and in-depth examination from me at this time.

Accordingly, I have decided to create a dedicated file for this important amplifier: THE COINCIDENT FRANKENSTEIN FILE. This file contains everything I've ever written about the original Tektron/Frankenstein and the Coincident Frankenstein, as well as all the Readers Letters.

This is the second best amplifier, overall, I've ever heard. Only the Coincident Frankenstein has proved to be superior. The Vaic, now discontinued, was an all-out attempt to create a state-of-the-art SET amplifier in the late 1990's. (I wish I heard it back then!) Each mono amplifier weighs 65 lbs, and they cost $ 22,000 for a pair. As far as I know, it was built to Vaic's specifications by Mastersound, located in Italy. Its appearance, all chrome, is stunning. Its performance, when it came out, was a "breakthrough" for (SET) amplifiers.

The Vaic is outstanding in every sonic parameter; naturalness, purity, transparency, speed, dynamics, "imaging" and the frequency extremes are not only there for once, but the deep bass has real power (see the Pure Reference essay). This assessment assumes that the Vaic will be matched to the "right speaker", because, as a SET amplifier, it lacks feedback. It uses a VV52B DHT output tube, which is similar to a 300B, but it can handle far higher voltage and bias, so the power rating is over 20 watts per channel. Compared to the Coincident Frankenstein, the Vaic still sounds a little more "electronic" and it's also slightly smeared and veiled.

The (required) modifications are pretty straightforward; Teflon coupling capacitors, film capacitor bypasses on the power supply caps, and improved internal wiring. These amplifiers are rather rare, but worth searching for. There may be a newer version of this amplifier by Ayon, but they cost $ 30,000 (8 years of inflation I guess).

Further- For those "sceptics" who want to know what is the finest amplifier I've ever heard, that also has no association whatsoever with Coincident (whose owner, Israel Blume, is a close friend of mine), the Vaic is that amplifier. In short, if the Frankenstein M300B did not exist, I would be now (desperately) searching for a pair of these Vaic amplifiers.

There are other amplifiers available with even less power (using 2A3, 45, 50 output tubes etc.) that are (supposedly) even more revealing and purer sounding. None of them are References at this time, because we are unaware of a single model that even equals the performance of the Coincident Frankenstein (let alone surpasses it). If such an extraordinary amplifier is ever discovered, it will be reported. However, don't also overlook the fact that only a tiny number of speakers can actually be driven by these amplifiers. That "problem" is irrelevant now, but it's a serious and unavoidable issue that will have to be addressed by any prospective owner/user.

I have not heard these amplifiers myself, at least that I can remember, but one of my "associates" had a thorough listening session with them. This associate has extensive experience with DHT and SET amplifiers, along with countless "traditional" designs, and has a highly revealing system. Here are his observations at the time, April 2006, with some minor editing:

"The Wyetech Topaz 211 Mono amps are the finest sounding high powered SETs I have experienced. They have tremendous drive capability, excellent bass extension and punch and overall purity, while detail and transparency is very single-ended DHT like. They perform like big, pentode tube amps, in those amps’ area of strengths (dynamics, weight, etc.), yet possess the single-ended "magic".

Compared to the best SET 300Bs, or type 50 or 45 based amps, the Topaz yields a smidgen of purity, but it takes an exceptionally high resolution system for this to be noticeable. The Topaz is slightly more forgiving, with transients a tad rounded by comparison to small SETs. The compromise, in this area, is the smallest I have experienced in a high powered amp. The Wyetechs are superior to the Canary CA 339s in virtually in every respect. They are more transparent and more dynamic and gutsy.

Build quality is state of the art. Each amp weighs in excess of 100 lbs. All wiring is point to point, the power supply uses only polypropylene caps etc. Output trannies are the superb Audionotes*. To achieve the performance I am describing, the amps must be modified. The Solen metalized polypropylene caps have to be replaced with V Caps or other top of the line caps. Solen’s new polypropylene film and foil caps are excellent. They sound superb and are very reasonably priced. Also, all the power supply caps must be bypassed with .01 mfd – 1200 V film and foil caps.

For any speaker requiring more than 20 watts, and yet 45 watts is sufficient, the Wyetechs are the amps to have. Nothing sounds as good amongst the competition, or is built as well. For those who are satisfied with 7 watts, the Topaz will be slightly, but somewhat, compromised. Even under these conditions, if a more forgiving sonic portrayal (by reducing some of the rough edges of poorly recorded material) is desired, the Topaz is the amp of choice."

Personal Note- I trusted my associate's experience and judgement enough to have originally placed this amplifier in the "Medium Power", Class A. Recent developments have now changed its relative status. The superb, and also less expensive, Canary CA 339 (which he also brought to my attention), is also still within this same list, which means it is still a Reference, but it's no longer recognized as the "best of its type". However...

*Caveat- A reader (within an hour of the original posting!) informed me that the current version of these 211 mono amplifiers no longer have Audionote transformers, but are instead now using Bartolucci output transformers. We have NOT heard these latest models, so caution is advised at this time.

Meanwhile, my associate, who owns and auditioned the amplifiers, also sent me a short clarifying note concerning this issue:

"Mine are the older model with the Audionotes. Wyetech switched to the Bartolucci because Audionote ceased production of the output trannies. I have heard from a few sources that the Bartolucci is inferior.

(I) just read an old Vacuum Tube Valley report (Issue 9-1998), where a comparison of output transformers with 211 tubes was conducted. The Audionotes received a rave review, while the Bartolucci was found to be noticeably rolled off in the highs, with a colored, albeit pleasing, sound overall."

Latest Update- I just received this update from my same trusted associate. This entry focuses on the 211 output tubes. Here it is, with some slight editing:

"A couple of days ago, I replaced the stock Valve Art 211s with NOS GE VT-4C (211) –Manufacture date–Aug /1944, and the resultant improvement in sound staggered me. ...The leap in sonic performance was greater than any tube substitution I have made. As good as the Topaz was prior to the tube change, the GE 211s wrought a refinement to the sound that was simply not there before. The typical Chinese tube glassiness (apparent with the Valve Art 300Bs), was eliminated and replaced with a silky smoothness that I did not believe a 211 capable. Overall purity and transparency was enhanced, as well as a lowering of the noise floor. A stunning improvement to be sure. There is no question that I have not heard a single ended amp, with this power, sound as good."

The former audio manufacturer, Golden Tube, came out with (at least) three amplifiers using one 300B output tube per channel. Two of them were MONO. One of them, the original design, used a 6SL7 input tube. The result is an amplifier of between 8 to 10 watts in the midrange and upper bass, depending on the brand of the 300B used.

The later mono version had the option, with a switch, of using a 12SL7 or a 6SL7. This model is also a Reference, but not when using the 12SL7. The third version was a stereo amplifier, which also had a different circuit, and didn't sound as good. It had some some good qualities, but it was not the equal of the two monos, and it is not in this class.

The stock performance of the Golden Tube 300B is not equal to the superb Wavelength Cardinal, or even the much more powerful Wytech Topaz for that matter. Fortunately, the Golden Tube can be extensively modified. When that is accomplished, according to my associate who made direct comparisons in his own system, it will not only equal, but even exceed both the Cardinal and the Topaz amplifiers in purity, transparency, immediacy and naturalness.

To describe its greatest, and most important strength in the fewest words and in the most direct and simplest terms:

Unfortunately, it can't come even remotely close to any "normal" amp in sheer power, bass extension, control and impact.

It is still in this class only because of its (potential) state-of-the-art midrange and highs and its (relatively) very low price, $ 2,000 or less used. This means that it can exceed the performance of any amp I've ever heard in a "bi-amp" situation, If extra power is Not required. Virtually the entire insides must be gutted and then replaced with the finest quality parts available. The entire procedure and the better tubes will cost another $ 1,000, or more.*

Most important, it must be used with high sensitivity speakers (minimum 92db and preferably higher) with a benign (above 6 ohms) impedance. The size of the listening room may also become an important factor because of the limits of its power. The good news is: If you do find speakers that work with them, and I have, than virtually all other amplifiers will sound unsatisfying in comparison. This company is now, sadly, out of business, but the Reference designation stands.

The Golden Tube requires either the KR 300BXLS output tubes to reach its full potential.

* I am planning to describe the modification of this amplifier, in detail, within a new section on Modifications to be posted in the future. It should also provide a "blueprint" and general overview for modifying other tube amplifiers.

CAVEAT: In practical terms, this amplifier, and virtually all the other similar 300B designs of 7 or 8 watts, is an upper bass, midrange and tweeter amplifier only. Even then, it will still only work with certain, high-sensitivity and high-impedance designs. The only exception may be the Wavelength Cardinal, which has considerably lower measured bass response. This means, that with very few exceptions, another amplifier should be used for the frequencies below around 80 to 100 Hz. 'Reviewers', manufacturers and dealers who advise otherwise are doing a true disservice to audiophiles.

According to my associate, this amplifier combines this second greatest overall amount of purity, delicacy, control, weight and authority of any amplifier he has ever heard in his 30+ year audio life (including the CAT JL-1 above). These are his own (anonymous) words, verbatim:

"The first amplifier that seems to do it all. The 'iron fist in a velvet glove'. 50 watts of 300B sound. That is, all the finesse, purity, transparency and low level detail retrieval combined with weight, impact, explosive dynamics and incredible bass. This amp does everything at the highest levels of excellence, Beautifully built, (1” brushed aluminum face plate- finest trannies, choke filtered, Hovland caps, huge power supplies) and extremely reliable.

Output Tubes – 4 300Bs in a push-pull parallel configuration
Input- one 6SN7
Driver – one 6SN7
Rectifiers- pair of 5U4Gs

On sensitive speakers, this amplifier sounds gutsier and more dynamic than the ASL Hurricane, and destroys it in every other parameter of performance. The CA-339 will successfully drive virtually all but the most insane speaker loads (i.e. Thiels, Martin Logans, Avalons etc).

Might not equal a superb SE PX25 amp at its greatest strengths, or a SE 300B, but it comes frighteningly close. In all other areas, the CA-339 is an order of magnitude superior. $14,000 US/pr ain’t cheap, but this is one of those rare instances in audio where it is actually worth it."

Personal Note- I haven't heard these amplifiers yet. Canary has another amplifier that is supposed to be even better; the Reference One Mono Blocks. None of us has heard them. They also make a number of preamplifiers, which we haven't heard. Unfortunately, they are all line-stages. No phono-stage is available according to their website (See Links File).

It must be stressed that these amplifiers have only been auditioned, as described above, on "easy" loads, meaning both high-sensitivity (above 90 dB) and high-impedance (above 6 ohms). Speakers that are insensitive, and/or with low/varying impedances, may not be suitable.

Further Notes- A reader has sent me three letters with his observations about them. I find his letters particularly relevant because he has other highly regarded amplifiers and he has compared them directly with the Canary. Here are his three letters, with only minor editing:

"I just saw an update on your web site about the Canary CA-339, and I thought I'd get my oar in on the subject.

I've owned a pair of (Coincident) Total Victories for about a year... As my aspirations for my system have grown, I've started looking for the perfect amps to drive them. So far I've gone through a Sugden Au51P, a KR 18 BSI, a pair of Coincident MP300Bs, a pair of Wavelength Tritons and a pair of deHavilland Aries 854s. About two and a half weeks ago... I took delivery of a pair of CA-339s.

I never imagined an amp could be so wonderful. Their sound is "complete", in every sense of the word. They have complete frequency response, complete dynamics, complete resolution, complete tonality and complete soundstaging. Their sound is completely natural in every regard. In fact, one of the things I've noticed about them is that the sound is so natural you don't even notice it, until you suddenly realize that what is making the music so breathtakingly real is the fact that the amps are doing everything right.

The source is an Audio Note 4.1x Balanced Signature DAC, and I'm currently using an Audion Premier two-box line stage... I have a CTC Blowtorch on order to replace the Audion, and I suspect that will tell the tale of the ultimate quality these amps are capable of.

...Anyway, at this point I completely agree with ...(the posted) assessment of the Canary amps - they are a match made in heaven with the Total Victories."

"I'm in the middle of re-tubing both the (deHavilland) 845s and the Canaries, and I'll provide more thorough impressions once all the tubes have arrived and settled in. Here's a preliminary look at where things sit right now:

The Canary CA-339s have their factory stock ElectroHarmonix 300B's, EH 5U4GBs and a set of black base RCA 6SN7GTBs. The deHavilland Aries 845Gs came with Russian 6AU5s, Russian 6SN7s, and Chinese 845s. In these configurations the Canaries were decisively superior in most regards to the 845 amps - better macro and micro dynamics, much better transparency, better frequency extension (especially in the bass), more precise imaging, a more open soundstage and more harmonic development.

I have since retubed the 845s with RCA black base 6SN7GTBs and KR 845s. It is now a much closer contest, and for the right listener the 845 is now the better amp. The dynamics of the Aries are now close to the Canary, the imaging is almost as good, the frequency extension in the treble is as good while in the bass it's not quite there yet. The soundstaging of the 845 is better than it was with the stock tubes, but still doesn't have the openness of the Canaries. In the area of harmonic development and density, however, the 845 amps are now decisively better than the Canaries. The sound is richer and fuller, with a very satisfying "big" tone. In addition, their sound is more relaxed. In comparison, the Canaries are revealed to have a slightly thinner tone, with a touch too much sparkle (verging on a bit of edge).

At the moment I'd characterize the 845 amps as "music-lovers' amps", while the Canaries are more "audiophile" amps. There's no question that the Canaries produce more venue information, develop a more explicit image and have more "balls". On the other hand, the Aries make listening to most classical, jazz and all folk music an unalloyed pleasure. With them I just sit down and sink into the music.

This is all subject to change over then next two weeks, though. I'll be completely retubing the Canaries with Philips ECG 5U4GBs, RCA red base 5692s and KR 300BXLS, which should dramatically change their sound. In addition, the KR 845s in the Aries are still brand new, and probably need about another 48 hours to really start showing their chops. I'll let you know how things go."

"I have some more observations on the Canary CA-339 following two months of break in and extensive listening.

I re-tubed them with KR 300BXLS power tubes and RCA 6SN7s. They love the KR tubes, and are now by a wide margin the best amps I've heard on the Total Victories. They achieve this through a combination of exceptional dynamics, total clarity, complete tonal neutrality, and a full realization of both the tonal and spatial properties of the recordings. They are completely at the service of the music, whether it be rock, jazz, blues, folk, classical of any sort from solo instrumentals to full orchestra, or anything else. They do both intimacy and scale with equal conviction. They sound utterly effortless. They impart a sense of realism to the recreated soundspace that is just plain spooky.

I've compared them to my deHavilland Aries 845G, which I have retubed with KR 845s. To be blunt, there is no contest. While the 845 is a very pleasant amp, it is obvious at all times that is is imposing its signature on the music. In contrast, listening to the CA-339 amounts to simply listening to the music.

While there are better amps out there for some applications, I can't imagine anything much better for use with the Total Victory or any other reasonably efficient, transparent speaker. My search for reference quality amplification is unequivocally over."

Personal Notes- Unfortunately, the KR 300BXLS is an expensive tube, but it appears to be a requirement if the owner wants to maximize the performance of the Canary amps. Considering the retail cost of the Canarys themselves, and the build quality and increased longevity of the KR tubes, I feel the extra cost is still reasonable and well warranted in the long run for the improvement the reader describes.

So far, it must be kept in mind that all the above accolades heaped on the Canary amps are by audiophiles who are using high-sensitivity speakers with a high impedance. I'm still waiting to hear some observations by owners of other types of speakers.

Based on the reader's second paragraph of his third letter, which is what my associate also told me in almost the same exact words, I can't remember the last time I've looked so forward to hearing an amplifier. Now I'll have to talk my associate into also getting those KR output tubes.

Most Recent Canary CA-339 News- One of my associates has informed me that the Canarys require high quality 300B output tubes to reach the performance that has been described previously, and which enabled them to be one of only 3 amplifiers within Class A. The lowest performing 300B tubes which are recommended are the Electro Harmonix Gold Grids. An alternative 300B, the Valve Arts, also available from Canary, is NOT recommended. My associate informed me that the Valve Arts seriously compromised the performance of the CA-339. On a similar note, the stock Chinese 6SN7s must also be changed to high quality NOS types, of which there are many choices. Without both of these tube optimizations, the CA-339 will not perform at the highest level, and is not a Reference. (2/05)

Most recent communication (3/05)- Below is some important information concerning these amplifiers, from "the horse's mouth" no less;

"I read your latest posting on our CA-339 and wanted to address the 300B position. A few customers have emailed and called me asking whether or not we supply output tubes with our amplifiers. On our website it clearly states that we do not supply them but apparently a little confusion exists.

For the record, all tubes (including output tubes) are supplied with our EL-34 based amps. With regard to the 300B amps, no output tubes are supplied and we neither recommend nor supply output tubes for any of our 300B amplifiers. As a convenience to our customers, we sell a number of 300B brands but do not endorse or recommend any of them."
Bill Feil
AudioFeil International
"Sound Products/Sound Solutions"
716-400-6177 Days/Evenings/Weekends
www.audiofeil.com

Personal Note- My associate highly recommends the Electro-Harmonix Gold Grids, especially for the money, while one reader, who has used a variety of 300Bs, feels that the KR300BXLS, which is much more expensive, is definitely superior to all the others he's heard, including the Gold Grids, and will elevate the amplifiers to a new performance level.

Further- I received this letter from Bill Feil, owner of AudioFeil International, who is the Canary distributor in October 2005. I feel this information will be important to the owners of these superb amplifiers. There's very little editing:

"...I want to call attention to both you and owners of the Canary CA-339, a moderately inexpensive (vis a vis very expensive premium 300B tubes) way to kick up the performance of these amps. Having just brought another pair of them into my showroom, I decided to leave the stock Electro Harmonix 300B as is. However, I installed a pair of 1960 Mullard CV 378 rectifiers and a pair of 1952 Sylvania 6SN7WGT in each amp. For less money than a pair of KR 300B's (these amps take 2 pair each keep in mind), the changes were breathtaking. Transients, soundstage, and articulation were noticeably improved. I thought your readers might be interested to know that, although these amps benefits from premium 300B tubes, these changes are a great cost effective compromise."

The Wytech is one of the finest overall amplifiers that we are aware of at this time. Its power rating appears "modest" (22 watts, 90 watts peak), and it does not break any new sonic grounds, but the "good news" is that this amplifier can virtually equal most amplifiers we know of in most areas of music reproduction.

To be specific: This means that it has much of the pure, natural, immediate and liquid qualities of the finest of the ultra low-power (under 10 watt) single-ended amplifiers, while still sounding as "gutsy", dynamic, and controlled as many more powerfully rated amps. Despite the standard "BS" regularly written in audio magazines, exceedingly few other amplifier have ever been able to legitimately make this claim in the past.

In short, this amplifier has excellent overall performance, especially at its price of $ 9,250, direct from the manufacturer. It is exceptionally well built and it is also ultra-quiet during operation.

Now for the "negatives":

1. This amplifier uses 1150 volts on the plate to get all its power from just one output tube (the main reason for its purity), so this isn't the amplifier to "play around and experiment with" inside.

Touching the wrong spot would be the final mistake of that person's life.

2. This amplifier is dual-mono, but on just one chassis. It is very large and bulky, weighs around 120 lbs., looks industrial, and it is much more difficult to place (and hide) than mono amplifiers. (This is the reason that I was not able to use it in my own system.)

3. This amplifier will not sound as described with the many low-sensitivity and low-impedance speaker models that are on the current market. This is just one more good reason to avoid those frustrating and self-defeating designs.

4. These amplifiers are custom made, one at a time (by owner and designer Roger Hebert), so there may be a waiting period for them. As far as I've been told, only the earlier (and inferior) model, using 845 output tubes, was ever sold "retail".

5. These amplifiers can be improved with better tubes, particularly the 6SN7 input tube and the 6BX7 driver tube. The 572 output tubes have no superior replacements at this time.

MONOS- There are also Wytech's own mono amplifiers, the 572M, which are a unique single-ended design using two 572 output tubes and two output transformers per channel, to minimize inductance.

They are 45 watts per channel and are $ 18,500 for a pair. None of us have heard them at this time. Other listeners, who have made the comparison, have reported mixed messages; some of them preferring the monos, and others describing the only advantage being the increased power. Some have even mentioned that there was an actual sonic (along with the obvious theoretical) disadvantage caused by configuring the two output transformers in "parallel" or in "series", depending on the speaker impedance.

One of us has compared two of the stereo amplifiers to just one. Despite the fact that the two stereo amplifiers had the advantages of both biamping and total mono separation, there was virtually no sonic improvement. This means that the stereo version sounds the same as the mono versions of the same amplifier. That is quite an accomplishment.

CAVEAT: There is actually more than one version of the Topaz amplifier from this company. The "original" Topaz used the 845/211 output tube. That is the model to avoid. It was still "excellent", but nothing "special". I know, I heard it in my own system. For some inexplicable reason, the manufacturer decided not to change its model number when he changed its design.

The current models only use the 572 output tube. This is the only model that is a Reference. Accordingly, it is safest to order a brand new amplifier and simply ignore any used models that come up for sale. This company also makes a "budget" amplifier called the Onyx, which also has decent sonics and good build quality, but it is also nothing "special".

FURTHER- I recently received news from a reader about two interesting components from Wyetech Labs, who have one of the finest audio "track records" in the last decade. One of them is new, while the other is an update of its most famous model. Here's the letter, with minor editing:

"Maybe you already know this, but there is a "new" amplifier from Wyetech Labs. It is the Sapphire 300B monoblocs, (Parallel) SET based on 300B tubes. Here's the link:

http://www.wyetechlabs.com/amps/sapphire/index.html

Also, there is a new version... of the Topaz, the Topaz 211C. The 572 tubes have been replaced by a new brand of 211 tubes.

http://www.wyetechlabs.com/amps/topaz211c/index.html"

Personal Observation-First Viva, and now Wyetech, has replaced its flagship model using 572 DHT tubes with a 211 DHT. I was under the impression that the 572 was the superior tube with more potential. So what's up? Well, readers should be made aware that the Svetlana 572 tube is now DISCONTINUED, and the remaining stock is both drying up and now rising in price. I think these two manufacturers are simply reacting to the reality of what is practical to build today. (12/05)

This amplifier is similar in design and competitive with the Topaz. It is made by the Italian manufacturer VIVA. The model is called the Aurora. It also uses a single 572 output tube, but these are "all-out" mono blocks, using in-house output transformers and they have the further advantage of using another 572 as the driver tube. Even more surprisingly, two more 572s are used as rectifiers, but that can be a mixed blessing.

There are some "downsides". The power supply is not as large and sophisticated, and the passive parts don't equal the quality of those within the Topaz. Both of those disadvantages can be addressed with various modifications, which should not be that difficult to do within such a large amplifier.

These amps are custom made only, and cost $ 22,000 a pair. This means that they will probably never be a Reference new, because the price differential with the competing Topaz is just too large. A used pair, with modifications, is another matter, because these amplifiers sell for half-price or less on the second-hand market. Their cosmetics are stunning.

VIVA now makes a very similar amplifier, using the more powerful, but usually less accurate and pure, 845 output tube. It is still called the Aurora, believe it or not. (Is there a fashionable trend to confuse potential purchasers?) An associate and I heard this new 845 amplifier at the 2004 CES and were very impressed with it, so this model may be something to look into.

Auditions- We auditioned the 572 Vivas a number of times with mixed results.

I auditioned the Vivas (stock) on my (now former) store system (CD based and with Coincident Super Eclipses) and on my own system (analog, and with the Ars Acoustica System Max).

On the store system, the sound was the best I ever heard with it, by far. Several customers, who were very familiar with that system, agreed with me. In fact, one of them, a very critical listener, said that it was the first time he had ever enjoyed the Super Eclipses. The sound was far superior, overall, than with the Manley Retros or the Altec/Tutay. It was incredibly natural and full bodied. It retrieved a considerable amount of musical information, which was almost always lost with other amplifiers.

I, and every other person who heard this system, couldn't have been more impressed. However,...

I then put the Vivas in my own system. First on the subwoofer, where it didn't have the best impact I have had, but it was superior in the most important areas; harmonic structure and the retrieval of low-level information; ambience, decays, space etc. (The Vivas on the bottom, and the Golden Tubes on top, was the best sound I ever experienced at that time. Every person who heard this combination, agreed with me.)

Next, I connected them to the main speakers, where it competed with the Golden Tube 300B mono amplifiers (above), which are highly modified. This time they didn't have the purity, immediacy, transparency and the ultra low sound-floor of the Golden Tubes (neither does any other amplifier I have ever heard). The Vivas had more of an "electronic sound", though they still demonstrated their previously described strengths. I, and another of my associates, preferred the Golden Tubes. One of my customers then purchased the Viva amplifiers just before I moved to Florida.

Prior to this...

Another one of my associates had the same Viva amplifiers at his house and also compared them to the Altecs, the Manleys, the Golden Tubes and the Topaz. He preferred the Vivas to the Altecs and Manleys, just as we did and for the same reasons. He also preferred the Golden Tubes to the Vivas in the midrange and highs, again agreeing with my conclusions. As for the Topaz...

He preferred the Topaz overall. He felt the Topaz equaled the Vivas in its strengths, but had more dynamic power and was also noticeably superior at the frequency extremes. He was so impressed, that he ended up purchasing the Topaz.

I then heard his system with the Topaz, twice, but the sound was not as good, overall, as what I heard with the Vivas at my place, though I agreed with him that the Topaz had better frequency extremes and more dynamic power. (Two of my other associates agreed with my assessment of his system compared to the system in my store with the Vivas and Super Eclipse.) He explained that the problems we all heard were caused by his speakers (Coincident Victory and Total Victory) not being broken in yet. So this is my problem.

If I take this associate at his word, where do I place the Viva? Probably "Class B", with a caveat that it is a Reference only at a used price, since the Topaz is much less expensive new, and it is better.

However, what if he is wrong? Because he couldn't hear the strengths of the Viva through his speakers, which were not yet broken-in, or for some other reason. Also, the Vivas have room for serious improvements, while the other Class A amplifiers do not. Additionally, the Vivas are noticeably superior to even the finest of the current Class B models.

The Temporary Solution: I am going to place the Viva (used only) in Class B. I know they are at least worthy of that designation. They may be a Class A amplifier, but I would like some confirmation, based on a thorough audition. So far, they came in second to the Golden Tubes in my system, and, according to my trusted associate, second to the Topaz in his system.

They will have to be superior, or at least comparable, to one of these two "Kings" in a serious "shoot-out" before they, or any other low to medium power amplifier, can join this very exclusive club. (See "The Reference Policy" within The Reference Components "Introduction".)

The Retro/Neo are superb, but do not have the ultimate transparency, naturalness and purity that the finest single-ended amplifiers possess; like the Golden Tube (modified) or the Wavelength Cardinal. However, their bass reproduction is superior to those simpler designs and they will work with a larger variety of speakers.

There are two requirements for optimization; the speakers must be sensitive (90db or higher), and also have a benign impedance (minimum 6 ohms, preferably above 8 ohms).

These are the amplifiers to consider if you still require more power than the 300B Single-Ended amplifiers (8 watts) can give you. Unfortunately, the Neos have a retail cost of $7,200 a pair, which is only $ 1,700 less than the superior Topaz. That is the reason why they are a Reference "Used" or "On Sale" only. The Topaz is still easily worth the extra $ 1,700, and more. (However, don't forget the Topaz's problem with size and placement.)

The Neos are mono, with two 300B output tubes per channel. They are very versatile: They can be switched from single-ended (12 watts) to push-pull (24 watts). They also have adjustable feedback, from 0 to 10db in 1db steps. They even have two inputs; a standard RCA and the other balanced.

They easily outperform all the Jadis single-ended designs that cost far more, and are even better than the Original ($14,000) Topaz. I sold and lived with the Retros, though I haven't heard the latest Neos myself, but one of my associates has, and in depth.

The most serious competition for these amps are the most recent (and now final) version of the Coincident 300B mono blocks (please see below), which have almost the exact same design, cost far less, and, according to at least one reader, even outperform the Neos. (I obviously never made a direct comparison myself, but I've been overall more impressed with the Coincident models than a highly modified pair of Retros. This was because they sounded closer to my Golden Tube 300B amps than the Manelys.)

The Retros were the previous model, now discontinued, and are very similar in sound and design. They had a retail price of $ 5,500 a pair. They were not quite as well built, and their sonics are not the equal of the Neos, but they are very close. (In fact, I now understand that some listeners prefer the more immediate sonics of the Retros.) The Retros are still a Reference because of their overall performance and excellent value for the money. The Retro must be used with the KR 300BXLS output tube, or else the amplifier will have both reliability problems and less than optimum sonics. They are expensive, but worth it. There is also a "bonus"; the Retro sounds its best with this tube.

The newer Manley NEO design is not as hard on its output tubes, so virtually any 300B will work with it, but the KR is still an excellent choice because of its sonics. (7/03)

This "vintage" Altec is a fantastic amplifier. It could be the "dream" amplifier for many audiophiles. I didn't list it initially because of the many hurdles to get an optimized working pair, and the potential danger in using them. Let's discuss the sonics first, and then tackle the remaining issues.

This amplifier, after it is fully modified, can compete with virtually any push-pull amplifier in the world. It uses only two 811A direct heated triode output tubes, but it can still generate over 150 watts per channel. It has a very high quality power supply with chokes, tube rectification, separate input and output supplies etc. The end result is a combination of tremendous power along with a lot, but not all, of the purity and transparency of the single-ended designs.

Other "high-power" tube amplifiers, that use multiple output tubes (8, 12, 16, or 20 per channel-especially pentodes) to create their power, can not compete with this simpler (and much less expensive) design. As usual, it is at its best with high-impedance loads, but it can still sound excellent in normal impedance loads as well, though it is not a good match with very low impedances.

Now for the inevitable "hurdles":

1. The original Altec 1570 series of amplifiers were designed and built for "commercial" and "industrial" applications; The U.S. military, sports stadiums, factories, auditoriums etc. They are very reliable of course, and are also downright ugly in appearance. There may have been many made 40 years ago, but now they are difficult to find. Their sonics, stock, are simply horrible. They sound "dirty" and have no bass. So they must also be modified.

2. There are very few people who can modify these amplifiers. The person who has, by far, the most experience, and has achieved the finest results we've heard, is Tom Tutay, a talented engineer who lives and works in Florida (Go to the "Links" section to contact him).

So after a pair of these are found in good condition, they must be sent to Tutay for his (very extensive) update. I don't know the most recent cost, and there are some options, but it will cost at least $ 3,000, or more. Considering the enormous amount of work involved, this is a very fair price. The total cost, including the amplifiers themselves and all the shipping, will be in the $ 5,000 range, unless you can "score" on the Altecs.

To put things in perspective, if such an amplifier were built in North America and marketed new in today's market, it would sell for a minimum of $ 10,000 and probably around $ 15,000 or more.

3. After all the above has been done, there is another important issue to ponder. The reason why these amplifiers can generate so much power with only two output tubes is simple; there is more than 900 volts DC on the plates. This voltage itself comes from the rare, high voltage power transformer, which has somewhat louder than average "mechanical noise". (The extra expense and difficulty in finding and utilizing very high voltage components is the primary reason why contemporary amplifier manufacturers haven't just copied this design.)

Unfortunately, there is a potential danger to this design. The 811A output tube receives this high voltage from an (easily accessible) cap on the top of the tube, and not from the usual, inaccessible tube pins within the chassis.

This means that anyone (or anything) who removes this cap while the amplifier is "on", or even "off" for a short period of time, and touches the internal metal part, can be electrocuted. I realize only a reckless fool or someone incredibly ignorant would do this, but I felt it should still be mentioned.

The Altec came with a perforated, protective cover which made it impossible to reach the cap, but it may be missing, and some people may prefer not to use it because the 811A output tubes look "cool" when they are "on" and all "lit up". This is highly unadvisable.

My advice is to do whatever it takes to make these plate caps inaccessible to others; a replacement cover, screen etc. Don't worry about "ruining" the appearance of this amplifier, it can't be made any worse than it already is. Once that is done, this amplifier is as safe as any other tube amplifier, and very reliable.

One final concern also deals with the Altec's very high voltage. A reader has informed me that an electronics designer warned him that the amplifier can "emit high radiation levels".

The designer's advice to an Altec owner is simple: "He will want to distance himself as much as possible from those amps..." This advice is also applicable with any other electronic device using high voltages; such as televisions, some older computer monitors and even "typical" tube amplifiers etc., so this information doesn't compromise the Altec 1570's Reference designation except in very highly unusual circumstances. Tom Tutay, the modification expert and engineer, also feels the amplifier is "very safe". (20 or more of these Altec amplifiers were used in the Astrodome and they were on 24 hours a day. The engineers who worked in near proximity never had any problems with them.)

Further (2/05)- A reader sent me some information and observations concerning these two very different amplifiers. Here they are, slightly edited;

"Did you know the Altec 1570 is an ALL class B amplifier;-) What a sweetheart. Wish I bought a pair years ago. The first time I heard them (was) on a pair of MBL 101's. I couldn't believe it.

Also the CAT JL2 is definitely better than the JL1 with one reserve, the bass is better on the JL1. For the bass, you move up to the JL3."

Personal Notes- I had no idea the Altecs could drive the MBLs. All I can add is, despite my best efforts, I haven't found a better bass amp for my own system, at least so far. I do have a new "contender" in the works. If everything goes to plan, I'll compare them this Fall, after the Hurricane season.

FURTHER (11/05)- I received some important information from an "associate" concerning this excellent amplifier (which I still use myself as a subwoofer amp). According to my associate, Magnequest is now building an updated version of the Altec's output and interstage transformers.

The output transformer is the real news, since it will be flat to 20 Hz, and will even have a 4 ohm tap. This is excellent news for people who will use the Altec with full-range speakers and/or low impedance loads (like me!). I'll post more information when I find it. I checked out Magnequest's website myself, but I found nothing on these transformers. Finally, they are supposed to cost $ 200 each, which sounds reasonable to me. I don't know the cost of the interstage transformers, or any sonic or practical advantages they have over the "originals".

A reader just sent some information on how to further improve this already unique and excellent amplifier. It is simply a tube replacement, but this time it's not just the brand of the tubes, but the actual model of the (output) tubes that are changed. Here's the letter with some editing:

"...the true copy of the ("Taylor") 572b, made by the Chinese (Penta Labs), not Svetlana, are direct drop-ins for the 811A. The bottle is 'ST', and not straight walled like an 845/211 transmitter triode. Tom Tutay said to use it and wrote this in his hand written manual which also gave the general history of the Altec amp along with upgrades, etc.

Biasing the tube is easy and a direct drop in for the vintage 811A...All we know is that after all the tubes were dialed in, it was like going from a weak V-8 to a big V-12, with lots of head room or reserve just setting there. We liked the change for its bottom end and over all extension."

Personal Notes-This may be really good news. I will verify all of this with Tom Tutay myself, and then try this "modification" on my own Altecs to see what results I get. I only use the Altecs with my system's woofers, but the improvements, especially in the entire bass frequency range, should still be easily noticeable if this reader is correct.

Caution- Audiophiles who already own the Altecs should NOT simply replace their currrent tubes with the 572B. Be patient until you find out exactly which brand(s) of 572B is/are recommended and the correct biasing for that tube. We're talking 900 volts here, so don't do anything until you know for certain that it's safe.

I recently asked Tom Tutay, the person most intimately familiar with this amplifier, about switching the output tubes from the stock 811A to the 572B. Tutay informed me that it's no problem to make the switch; the amplifier just has to be re-biased, as with every change of the output tubes. The actual bias, and everything else, remains the same.

Tutay also informed me that he felt the amplifier's resulting sonics, with the 572B, were "different", and not necesssarily "better", depending on personal priorities. Still, considering the relative ease and small monetary investment involved, I feel the enthusiasts of this amplifier should try it out for themselves if possible. (But please, never go inside the 1570B unless you know what you're doing- The potentially lethal 900 volts remain on the plate.)

I received further information about the 572B output tubes for this amplifier, which can be replacements for the stock 811A. Here it is, with slight editing (My Bold):

"(I) wanted to respond about the current production 572b. There is an eBay tube seller that offers a year warranty, fully understanding they may be back-up tubes, and not be used imediately. Penta and all the rest only offer a 30 day warranty from the day of purchase. BTW, all the 572b tubes are made at one plant in China, but some sellers will take the time to burn them in and really test them because short-wave radios put a lot more current on the tube than audio use does.

The eBay seller is: k5svc, and has a store with tons of parts and tubes for short wave radio people. His email address is: unclegeorgessurplus@yahoo.com "

The "Hurricane" is a large, heavy (65 lbs) and powerful (200 watts per channel) mono power amplifier built in China. It uses 8 KT-88 and 3 6SN7 tubes per channel.

It is a "push-pull, ultralinear design with point-to-point wiring (no circuit boards), two power transformers (one 'push' and one 'pull') and 0 NFB". The latest models use special oil and paper capacitors (more on this below). The biasing is very easy with a large LED readout. Amazingly, the price is $ 4,400 for the pair! (Compare that price to equivalent models from Audio Research, Conrad Johnson, McIntosh, Jadis, VAC, Manley, VTL etc.)

This amplifier has been extensively auditioned by the same associate who owned the rare and expensive CAT JL-1 mono blocks, now in "Class A". A comparison of the two models was made on his own (very high resolution) system. The results are...

The CAT still has some advantages, but my associate also claims that the Hurricane is close enough to be "competitive", and it is only around 1/5th the cost of the CAT. He was impressed enough to purchase a pair.

Paraphrasing his description of them: "Tremendous dynamic range and control, huge and focused soundstage, along with a surprisingly natural and refined sound, especially considering its size and power. A breakthrough for the money."

I have also heard them myself, on my associate's system, and can now verify his above description. In addition, I was able to observe that it still obscures some "inner, fine detail" and loses other important musical ("low-level") information, which is the strength of the finest single-ended designs I've auditioned. Its "sound-floor" is also very low for a high-power tube amplifier, but it's still higher than the best of the simpler designs.

Since our initial Reference designation of this amplifier in May 2002, and my later audition of them in September 2002, another version came out with oil and paper coupling capacitors, which are made by the same factory that designs and manufactures the Hurricane. (There were a few other minor changes, but they are sonically insignificant.) My associate had a pair of this new model and has made extensive comparisons with the original amplifier.

(The "original" version of the Hurricane used metallized MIT polypropylene capacitors. These are best described as "utilitarian" and are both the cheapest and worst performing caps within the entire MIT line-up. Their film and foil polypropylene and (top-of-the-line) polystyrene are both much superior. I know this for a fact, because I have more than a decade worth of experience with all of their capacitors, including within my own systems.)

To my associate's surprise, he much preferred the oil and paper capacitors, despite their generic reputation for normally being "soft, weak at the extremes, blunted, veiled etc". He informed me that these new capacitors were either equal or noticeably superior in every area of music reproduction to the budget MIT equivalents. The overall improvements he heard are one of the reasons why this amplifier was originally moved up to this higher class (the other reason is that I was initially cautious because of our previously unsatisfactory experiences with some other components manufactured by this company).

Meanwhile, The Absolute Sound (TAS) (Harry Pearson no less) gave this amplifier a rave review, calling it, in effect, "the best amplifier in the world". They then went on to badmouth the new oil and paper caps. They are wrong on both counts.*

While this amplifier is most likely the best value for a high-power amplifier now available, which is why I listed it in the first place, it does not equal the better single-ended-triode designs in their important sonic/musical strengths. I know this for certain, because I compared this amplifier with a superb, but not "state of the art", SET amplifier myself (the Coincident MP 300B-see below). My associate also felt that the Tenor 15 Wp was superior in its primary sonic strengths, and he now prefers the Antique Sound Lab's own AQ1009 in overall performance (see below).

Yes, this model has its own important sonic advantages over the best of the SETs, which just simply means that it is impossible for there to be a single "best amplifier in the world" (at least as of today).

As for the capacitor issue, I trust my associate's hearing and competence much more than I trust Harry ("120 dB") Pearson. The fact that Pearson can't even easily hear the sonic downsides of the Hurricane is alone enough to seriously question his present hearing ability. Fortunately, the distributor and manufacturer appear to have solved this issue themselves. (See below)

* While I have a serious disagreement with Harry Pearson as to the Hurricane's ultimate merit, I do give "HP" (and TAS) credit for finally bringing recognition to this amplifier. Recognizing "unknowns" and "little-guys" may have been typical behavior 20 years ago, but that is no longer the case today for the the major magazines.

Further TAS Controversy- In the "Reviewing the Reviewers" file, within The Absolute Sound sub-file, please read the correspondence between myself and Randy Tomlinson for more information, opinions and experiences concerning this amplifier and compatible speakers etc. (3/04)

My associate has now extensively auditioned the latest (March 2003) version of the Hurricane. It has a "Triode switch" plus it uses new, multi-layer, paper and oil capacitors, which cost 20 times what the older MIT capacitors costs. He has informed me that (when it's operating in triode) this new Hurricane noticeably outperforms the two earlier versions. He claims it is superior in virtually every sonic parameter, including dynamic intensity, transparency and purity.

These significant improvements are the reason why the Hurricane has, once again, moved up in these listings. However, it still does NOT equal the finest SET (or OTL) amplifiers in their greatest strengths. Of course, many, if not most, listeners may still prefer the Hurricane's own strengths. (In fact, a number of listeners preferred the Hurricane to the Wytech Topaz in a recent shootout, even though they acknowledged the Topaz's superiority in its sonic "upsides".)

A few of my associates have had an opportunity to try out different output tubes. They prefer the Svetlana 6550C. The output tubes that come with the Hurricane, the Valve Art KT-88, are warmer in character, which many listeners may prefer, but lack some detail, purity and transparency. Actually, changing the 6SN7 input tubes will probably make more of a difference. NOS tubes from the World War II era are preferable. Unfortunately they are expensive, $ 50 or more, but they last a long time.

Bottom Line- Readers must demand only the latest model of the Hurricane, which includes the Triode switch and the latest multilayer oil and paper capacitors..

Further Listening- In early June 2003, I heard the absolute latest version, with the triode switch, for six straight hours, with a system, room and software (all LPs) that I am very familiar with. The results actually surprised me.

To put this bluntly; the more I (actually we) hear this amplifier, the less I'm impressed with it. It is a "breakthrough" of sorts. For an amplifier using 8 power tubes per channel, 4 "push" and 4 "pull", it has amazing performance, especially for the money. It is relatively clean, transparent, dynamic, neutral, "big sounding" and has excellent frequency extremes. It is competitive with, or better than, any other "big amplifier" I know, and at any price.

The Hurricane's problems become evident when you begin to compare it with "small amplifiers". It just doesn't have the immediacy, transparency, inner detail, purity and low sound-floor of the finest low and medium powered amplifiers I've heard. This is easily noticeable to any experienced listener.

Audiophiles who don't require the power of the Hurricane should seriously consider low-powered alternatives, but for all those many audiophiles who do need the power (50 watts or more), the Hurricane is the best amplifier news I can remember in my now long audio career. That is why it will remain in Upper Class B.

Finally, the Hurricane sounds much better when it's operating in the Triode mode. There is really no comparison. I write this only because I was told that some owners actually prefer listening in the standard Pentode model. This preference is a mystery to me, so it's safe to say that I don't share much in common with these listeners. (7/03)

Further- Here is a short note from a reader who owns a pair and who shared some of his recent experiences:

"You're right, triode is the only way to listen to the Hurricanes. Also, it helps to substitute Sylvania 6SN7 GTBs for the Chinese tubes. I also tried RCA red base 5692s, but I didn't care for them. In the Hurricanes the sound became darker with less detail. I was surprised.

One other note about the Hurricane's tubes. I found that changing to the Sylvanias sharpened up detail and definition enough to make up for the warmth of the KT-88s. I tried the Svetlana 6550Cs but found when used with the Sylvania 6SN7 GTBs, they made the midrange too forward, so much so that the vocals and instruments, such as tenor sax, seemed detached from the rest of the music. (In my system.)" (9/03)

"I am your reader with a pair of Hurricanes with Sylvania driver tubes. Well, that was then. Now I've found a combination of V-11 (driver) Tung Sol "Black glass, Round plate" 6SN7GT/VT-231,.... V-10 (driver) Sylvania "Stagger plate" 6SN7GT (both 1945 Vintage)... and in V-9 position (splitter) an RCA "Gray glass" VT-231 is pure magic. While I am sure there are other combinations that will yield good results, I now have tried 12 sets of vintage 6SN7 types in various combinations and have concluded that this combo is the best I have heard. Mixing tube types enhance the good properties of each tube type while minimizing their week points."(1/04)

This letter is from a reader who has the latest Hurricane and is using it on an electrostatic speaker. These are his edited observations:

"I have purchased the new Hurricanes and use Acoustats [heavily modified 2+2 with Medalion transformers, plus after market resistors and caps, impedance down at 3.5 ohm at 20 Hz, rising to 6 ohm, then down to 2.5 ohm at 20kHz]. ...I have had them for only one month, so what is still in store I am not sure; first impressions as follows: I noticed the bass to be extended although somewhat loose, the cellos are warm and full, the guitars are tactile and sing, the violins tend to lack air or extension, the pianos have good weight but again the high notes lack the last bit of clarity (that pearly ring of the upper mid and high open strings), the organs sing but are a little overfull in the bass. Power and impact are impressive." (5/04)

Note- Since this reader is using an unusual load for the Hurricanes, I asked him to continue to forward his observations which will also be posted here.

Caveat- There is also a 100 watt version of this amplifier, but my associate informs me that "it has none of the magic of the Hurricane". This is another example (and important reminder) of this company's inconsistency in performance.

This is a preliminary report from some of my associates. However, there is still enough information to know that this amplifier must receive a Reference designation.

First the facts: It is a push-pull amplifier using (2) 845 output tubes. The other tubes are (per channel) two 12AU7 and two EL-34. You can replace the EL-34s with KT-66, but the sonics will be degraded. There are five (5) transformers per channel! (Output, high voltage power, low voltage power, input and coupling.) The price is (a very reasonable) $ 5,300 for the pair.

The early models, stock, were superb in some areas, but "somewhat lean and not fully, harmonically fleshed out". They also used the same cheap MIT capacitors that the original Hurricane used. My associate replaced these MITs with the latest oil capacitors, built by Antique Sound Labs, and also used in the latest Hurricane. According to him; "big difference". The sound was fuller, purer, more detailed and with better bass.

This amplifier is only a Reference if the new oil capacitors are used. (The latest models may already include these oil caps, see below.)

My associate also made some direct comparisons, after replacing the capacitors, to two of the highest rated amplifiers on this website; the latest Hurricane and the Wytech Topaz, which is currently in Class A. He also had the help of several friends for verification. The comparisons were made on high efficiency speakers, playing at both high and low volumes. The results were:

AQ1009 Vs. Hurricane- The Hurricane had slight advantages in power, dynamics and bass, but they were not significant. The AQ1009 was noticeably purer, more detailed and more transparent. Almost everyone* preferred the AQ1009.

AQ1009 Vs. Topaz- This time the results were exactly the opposite. The amplifiers were "similar" with "undemanding" music, with the Topaz now having a slight advantage in purity and transparency etc., but the AQ1009 was noticeably more dynamic and also had superior bass. This was especially noticeably with "demanding" music. This was a trade-off of giving up a little, and getting back a lot. Everyone preferred the AQ1009. The AQ1009s are also just half the price of the Topaz, and are real mono blocks.

*Further- Since that initial comparison, one listener, my associate, says he still prefers the Hurricane overall. It is his favorite amplifier, with the possible exception of the CAT JL-1, which he hasn't heard for a while, and is not available for a direct comparison.

Along with the mentioned advantages in dynamics and bass, he feels the Hurricane has more body and sounds more "right" than the AQ1009. He says he just "enjoys" listening to Hurricane more than the AQ1009. He stresses this is only true of the latest Hurricane with the latest oil and paper capacitors. (5/03)

Future- The above is based on only a few intense weeks of testing. More listening and comparisons are scheduled. Meanwhile, I was told that the latest models of the AQ1009 will contain the new oil capacitors. If true, no modifications will then be necessary.

More than a year ago, I forecast the future domination of Asian tube amplifiers within the North American audiophile community. The future may have arrived earlier than I thought, if not in market share as of yet, certainly in performance, especially for the money.

Tube Rolling- A reader has written to me since the above has been posted. He has more experience with the AQ1009 than anyone I know. This is what he informed me:

"As you may remember - I have these amps--the best tubes I have found are; the KR845---E80cc for 12AU7---and National Union (first choice) or Western Electric 350b. These are by far the best amps I have heard. The inputs/outputs need to be changed (to Cardas). I also changed the internal wire to JenaLabs. All the tubes, wire, connectors have been Cryo treated by Jenalabs (http://www.jenalabs.com/). With the changes stated above, better amps by 50%..........."

This same reader later added this information concerning the Western Electric 350b tube and the bias; "they can be dropped in---bias should be set 350 max..I run at 300-325" (7/03)

Further- After a request, a reader provided his (edited) observations concerning some of the finest amplifiers ever made; the ASL Hurricane, the ASL 1009 and the Altec 1570B (modified):

"...The Altec 1570B is maybe slightly leaner, the Hurricane more full-bodied. A slight edge in clarity might go to the Altec, and they are about even on power- both are extremely ballsy. Reliability DEFINITELY goes to the Altecs- these things have been champs in my system (I would NOT have sold these had I not needed to finance the ASL 1009s, and in some ways I still prefer the Altecs- an interesting toss-up...). Further on reliability, I am learning of some problems with the Hurricanes (blown resistors, etc.), and as compared to the Altecs, further issues also due to all those extra tubes. The ASL 1009s have been FAULTLESS however- in my opinion THEY are the champs of the ASL lineup- improved clarity and low-level detail over the Altecs, albeit with a smaller power output. Ultimately, if cash had not been needed for the Total Victorys in my large ~20' x 20' main room, I would be putting the ASL 60-watt 1009s on top, and the Altecs (or Hurricanes) on the bass in a bi-amp setup, and I would have a second, smaller, den-type listening room with the smaller Victorys and a pair of 12-watt Wavelength Cardinal X1s- THIS would be my ultimate setup..."

Extra- There is another amplifier from Antique Sounds Labs that uses ONE 845 output tube per channel, making is a true SET. It is the AQ1006. My associate has auditioned it extensively. The result: It is not that good. The problem is that it is not an "all-out" amplifier like the AQ1009 or the Hurricane, which both have large, stiff power supplies. Avoid it for now. (5/03)

I used to be a dealer for this company. This amplifier, and a simpler stereo integrated version of it, came out the year I left the retail business (2001), so I never had a chance to purchase one for the store or even audition it. The proprietor (not surprisingly) raved about it, and I heard other good things from a number of owners, some who had wide experience with amplifiers, but I wasn't in a position to do anything more than mention its "potential" to the readers of this website.

I finally had a chance to hear these amplifiers on a system I was familiar with, for a period that allowed me to hear it "in-depth", and also afforded me an opportunity to compare it with some of the other amplifiers on this list, including the Hurricane. In short, this is a superb amplifier, and very similar in basic design and performance to the Manley Retros/Neos.

It has exceptional low-level information and purity, noticeably more than the Hurricane, though it's not equal to what I've heard with the Golden Tube 300B, which is in Class A of course. It has excellent dynamic qualities, especially for its power rating, and unexpectedly tight and impactful bass, but the speaker I heard it with (the Coincident Victory) is an "easy load", so speaker choice is critical with this design. Of course, the Hurricane (and even the Topaz) is considerably more dynamic, "controlled" and impactful at higher volumes, and can be used with virtually any speaker.

This amplifier is very easy to bias and is very well built for the money. I think it is manufactured by the same company in China that (ironically) makes the Hurricane. In effect, it is an enhanced version of the Antique Sound Labs 300B amplifier.

2003 Update- I heard the most recent version of this amplifier when I visited Toronto in October 2003. I was very impressed. It was a significant enhancement over the earlier version, which was already excellent. The most obvious sonic improvements were in the areas of immediacy, transparency and purity. There was still a problem in the bass frequencies, which was blamed on the output tubes being used at the time.

The owner of Coincident, Israel Blume, informed me that he was now using superior coupling capacitors (oil and paper), input transformers and output transformers. These amplifiers should still be used only with high sensitivity and high impedance speakers, like most of the models from Coincident themselves. That's the only type of speakers I have auditioned them with.

While there, I also heard these amplifiers with very expensive ($ 125 each) and rare NOS 6SN7 input tubes. The improvement was only modest, so the stock (Chinese) tubes must be excellent. The output tubes were a different story. Blume first offered an optional update, but has since replaced the original tubes with the latest Electro-Harmonix 300B. The new retail price for a pair is now $ 4,000.

I made my semi-annual visit to Toronto, where I lived and worked for more than 30 years. I was there 10 days for mainly business reasons, but I did spend one entire day at an associate's house, where I had a lengthy, fascinating and highly productive listening session. I actually had some unprecedented experiences. One of these experiences, my/our observations and the final results and conclusions are discussed below.

Prologue- I've heard the Coincident amplifiers a number of times now, at great lengths and with both equipment and software I am intimately familiar with. The last time I heard them, in October 2003, they were simply superb, though they had problems in the bass, due to (according to the importer, Israel Blume) their (then) stock 300B output tubes. This time I heard them with the (now stock) Electro Harmonic Gold Grid 300B. There's no question they're a noticeable improvement over the former 300Bs. The bass is better defined, deeper, cleaner and with more impact and punch. There may be other improvements in the mids and highs, as Blume claims, but I couldn't confirm them in these limited circumstances.

I made this comparison myself. After a proper (30 minute) warmup, it soon became obvious that the MP 300B was to the AP 55 as the AP 55 was to the (described and remembered) Hurricane. (See Vintage Amplifier File for description.) In short, the MP 300B was cleaner, more transparent, more immediate, and less electronic than the AP 55. In turn, the AP 55 was still a little better in the bass and dynamically. This was all easily noticeable, but a particular comparison of two records demonstrated the sonic superiority of the MP 300B in a manner I've never experienced before.

The two LPs were:
1. John Klemmer-Touch-Mobile Fidelity, and
2. Dom Um Romao-Saudades-Water Lily.

It must be first emphasized that neither of these LPs is "demanding", in the sense that a Mahler symphony would be, since they're both "light Jazz", so the difference in power of the two amps was irrelevant. Also, I didn't intend to compare the recording quality of these two records, it just ended up happening because of the totally unexpected initial results. It all started innocently...

Both records sounded predictably excellent on the Stromberg-Carlsons, but I was immediately faced with a serious dilemma because, in a number of ways, the Klemmer/MFSL sounded better than the Romao/WL. This should not have been possible. Why? This was my dilemma:

How could the Klemmer LP, which I had placed in "The Honorable Mentions" (the lowest category of my record list, The Supreme Recordings) sound better than the Romao LP, which I had placed in "The Divinity" (the highest category)? My personal thoughts at the time were; "What the hell is going on here? How could I have been so wrong in assessing both LPs?" Then we played both of the LPs again, back to back, using the Coincident amplifiers.

Both of the records sounded better, but this time the Saudades LP "wiped the floor" with the Klemmer. The respective sonics were now the same as when I originally played the two LPs on my own system (where almost all of the posted LP evaluations were made); the Klemmer was still excellent, but the Saudades was simply incredible; a great record. Just as I remembered. What could have happened that would mask the previously obvious qualitative differences between them? (And to such an extent that their qualitative rankings were reversed?)

I've long felt, and have now finally confirmed to my own satisfaction, that to hear, and appreciate, the finest recordings requires an audio system that does "the least harm" to the sonics. To achieve this goal requires an audio system with a simple, well executed and matched signal path. Anything less will pervert the audio signal to such a degree that the subtle musical qualities, which distinguish "excellent" from "great" recordings, will essentially disappear. This will then leave only those relatively gross musical qualities which, depending on the peculiarities of the system, could be fortuitously enchanced or, just as likely, even further compromised. Thus the inevitable result; fruitless and endless disputes about which recording is superior, based entirely on how well the recording matches the unique strengths and weaknesses of that particular audiophile's system.

In this instance, the Stromberg-Carlson's pentode output tube, push-pull circuit, as good as it was, was not able to pass all the exceptional amount of subtle musical signals on the Saudades LP. In effect, only the lowest, common denominator parts of the signal remained to compare to the Klemmer LP. The Coincident 300B parallel SET amps, however, were able to pass on that previously missing musical information, which then reversed the LPs' respective rankings.

Prior to this experience, I've never before heard such a clear demonstration of the superiority of an (single-ended) amplifier using D(irect) H(eated) T(riode) output tubes in such a definitive manner. This was much more than a simple "improvement", since both records sounded "better". No, the qualitative improvement in performance was so fundamental, that we couldn't even make accurate evaluations of the LPs' ultimate musical recording quality without incorporating them within the system.

This defining experience that WE had (my fellow listeners were also equally amazed by this LP comparison) was something I wish I could have shared with the multitude of fellow audiophliles who are still looking for a perspective, direction and strategy that will not fail them in the long run. Once you find the correct strategy, and I strongly believe that I/we have, the components themselves are much easier to evaluate and eventually become "secondary", which is their proper place to begin with.

The CAT is the most versatile, "powerful" and expensive amplifier we have ever made a Reference. It is also one of the finest in overall performance, though that will obviously depend on speaker matching and personal listening priorities and tastes.

Only one of our (tight knit) group as heard this amplifier in depth. However, he has an "all-out" analog system and extensive experience with every other amplifier on this list, plus hundreds of others in his 30 year audio "career". Still, I will add a personal "caveat" at the end.

These are mono amplifiers that weigh 190 lbs. each! The "standard" model, which was both auditioned and purchased by my associate, costs $ 20,000 a pair. The "Limited" version costs $ 50,000 a pair. The output transformer weighs 55 lbs. by itself. The power transformers are even larger. This is a serious amplifier. The designer and manufacturer is Ken Stevens.

The JL-1 doesn't use (direct-heated) triode output tubes, like every other amplifier that has ever been in this class. It is also the first "push-pull" amplifier ever listed in this class. Instead, it uses (8 per channel) pentode tubes that are wired in triode. It is, like the more recent Jadis JA-80/200, able to work with 6550s, EL-34s or 6L6s. This particular model, used by my associate, was operated with 6550s.

(Important Note- A reader, who is also a distributor, informed me that this amplifier sounds best with the KR Enterprises KT-88s.)

The input tube (and phase splitter) are a 12AX7 and a 12AU7, plus there are two 6DJ8s used as driver tubes (which is unusual). The input tubes, as this is written, are still stock EIs from Yugoslavia, which will allow further sonic improvements to be made when the finest NOS tubes are used as substitutes.

According to my associate; "the JL-1s are the most emotionally exciting amplifiers I have ever heard". He feels they provide an overall "visceral" experience that is unique.

While they are rated at "only" 100 watts per channel, he claims they have more "impact, solidity, weight and control" than any other amplifier he has heard, and that includes many of the 500 watt (Jadis, Krell, Classe, Pass etc.) "monster" amplifiers, and the Altec/Tutay 1570 and Wytech Topaz tube amplifiers already on this list.

What about "refinement"; especially considering the CAT's triple disadvantages of a push-pull circuit, and 8 (pentode) output tubes per channel? He claims that the amplifier is still very pure, but not quite the equal of either the (also Class A) Wytech Topaz or the Golden Tube 300B in their greatest areas of strength; liquidity, purity etc. This observation is not surprising of course.

He felt that on digital sources, the differences were virtually inaudible, though on the finest analog sources, the above mentioned SET designs still had a noticeable advantage, but only on the best recordings, and even then, only where the music is simple and uncomplicated. On the other hand...

On high-power, complex orchestral works; he feels the JL-1s are so far superior in their (dynamic) strengths, that any "downsides" are "relatively trivial", and aren't worth talking about. This is the reason why he much prefers these amplifiers, overall, to any rival he has yet heard.

Are they really worth $ 20,000 (in parts, labor etc.)? My associate has taken the amplifiers (not literally) apart. He feels they are very well built, but still somewhat overpriced. Of course, we don't know what the unique and gigantic output transformers actually cost to build, but he felt they should sell, in an ideal world, in the $ 15,000 to $ 16,000 range. They still offer equal, or better, value than most of the amplifiers in the $ 20,000 range. (Of course, considering their sonic achievement, they are the best value we know of in that price range, or above.)

Personal Caveat- I only "heard" these amplifiers once but, if I remember correctly, it was in show conditions, which is basically meaningless. My associate's "taste" is slightly different than mine. I favor purity and low-level information somewhat more than he does, but those qualities are still high priorities for him also. I believe his "taste" is more "mainstream" than mine is, so most readers of this website will probably agree with his assessment and feelings concerning these amplifiers.

What I know for certain is - knowing him as long and as well as I do - if a picky person like him is so impressed and enthusiastic about these amplifiers as he is, they must be damn special, and that's why they are here.

Further- Since the above observations were posted, the Antique Sound Lab Hurricane became available. According to my associate, it is "competitive", though still not quite equal to the CAT. It is now, in Triode operation, in Class B (Upper). It is only $ 4,400 a pair.

CAT JL-2- This is their current model. It is a stereo amplifier, in triode operation. None of us has heard it, but I have received appraisals of its performance from some readers, and everyone of them has been very impressed with it. One reader recently wrote that he actually preferred it to the JL-l in a direct comparison. Here is the relevant part of his letter:

(The JL-2)..."drives my Soundlabs M-2s like no other amp ever has. If your colleague loved the JL-1 monos he would find the lower priced stereo version "purer" with a lower noise floor but still outstanding bass (but not quite as good as the JL-1s). I had the chance to compare them directly as I wanted the JL-1s to sound better. As I am a monoblock type of person. ...They only looked more impressive, sounded fantastic but not as fantastic as the JL-2. The JL-2 reminded me more of the single ended triode sound."

More Recently- I just received a letter from Ken Stevens, designer and owner of CAT, which describes the differences between the "stock" JL-1 and the (more expensive) "limited edition" version of the amplifier.

"a) we bias the output transformer like an SE amp Biasing greatly improves low level linearity and IMO is the reason for the greater immediacy and vibrancy of SE amps.(when the owner sets the bias to read "0.0" it is then optimal inside the transformer).
b) We use a low loss core material - 12 times lower hysteresis than silicon steel and also better linearity. The net result with BOTH improvement above is 90 TIMES (no typo) greater linearity between small and large signals in the output transformer. Our current amps, the JL2 and the JL3, also use this technology..." (4/04)

Further Thoughts on the CAT Amplifiers- I have nothing new, but fortunately, a reader with extensive experience, particularly with all-out phono reproduction (he's one of the ELP contributors), has forwarded his observations concerning CAT's latest amplifier design, the JL-3. Here they are, with all personal references edited out;

"I have switched amps to the JL-3's... Naturally there was a 'trial' period in which I could return the amps if they didn't better the Wavac's. Happily (for my back, they weigh a ton!) they did beat the Wavac's. The immediate impression 30 seconds into listening is that they are both more transparent and smoother (in the hi freq) than the 833's. The second impression, the one that is something of a shock, is how well they do bass. The bass is full, powerful, controlled and well articulated. The bass of the Wavac's is anemic by comparison. While the Wavac's are still marvelous in the midrange, the JL-3's take those qualities and extend them to both extremes. The Wavac's sound more like a good tube amp while the JL-3's sound more like live music. In that respect the JL-3's remind me of the ELP is the way that it brings life to the music and increases the listeners indolent with he music. Too bad the ELP is in Japan being repaired as I can't wait to see if the ELP still sounds as good with the JL-3's. For sure the JL-3's will reveal any shortcomings in the ELP. For 3 years I've assumed I would never own another amp beyond the Wavac's. After all, how can you improve on 100 watts, Class A, SE triode? (I) guess CAT has figured a way."

Personal Note- Every person I know of, including one of my associates, who has lived with these various CAT amps has been "knocked out" by them, and that even includes veteran audiophiles who have already successfully used the finest single-ended triode amps in their system. The CAT amps obviously have some special qualities, which other (pentode output tube based) designs are missing.

The Atma-sphere is an Output TransformerLess (OTL) amplifier, and the best sounding of its type that any of us has heard, so far.

Its power rating is a nominal 60 watts per mono amplifier, but is highly dependent on the impedance of the speaker. It cannot* be used with speakers with less than 6 ohms impedance, and it is at its best only with an impedance of 8 to 10 ohms and above, regardless of what the 'reviewers' and even the manufacturer's literature state.

At its best, meaning with a high impedance speaker, it has many of the qualities of the Class A amplifiers; neutrality, transparency, detail, excellent dynamic qualities and superior bass because of its direct coupling advantage.

The feedback used in this design is deliberately low and, if it is connected to high-impedance speakers, can be entirely removed, which further improves its performance. In fact, if this amplifier is totally stable with no feedback, that is the definitive sign that it is an optimum match with that particular loudspeaker.

It fails to make Class A because it lacks both the last degree of low-level musical information and the sense of immediacy that allows the listener to believe there is a direct connection with the performer(s).

Despite its appearance, with 8 output tubes per channel, the M-60 is actually a very simple design. The 4 input tubes are the amplifier's only gain stage, and they also double as phase-splitters. The output tubes operate as simple impedance matching devices, like a cathode-follower, and they have no gain.

This amplifier has a near cult status and there are countless ways to improve it. There was a kit available at considerable savings, but it was very difficult work and not for the beginner. It was discontinued at the beginning of 2001. The retail price is $ 4,650 "stock", with a number of upgrades available.

This company also makes larger and more expensive models, but their only advantage is greater power, otherwise they are not quite as clean, liquid, transparent and immediate as the M-60.

*Further- A reader has informed me of an accessory that may allow the owner of the M-60 to use it with a greater variety of speakers. Here is the information he sent me:

(The M-60) "mates well with speakers of low or uneven impedence when the "Zero autoformer" made and sold by Paul Speltz (see his web site) is connected between the amps and speakers. This may be done without speaker cables if the amps are located within 36" of the speakers. This raises the impedence by variable amounts so that the amp see 16 ohms or more at all frequencies. It is recommended by Atma-Sphere." (6/03)

The JA-80 is a classic design and the first component that Jadis ever made. It is in this class only if it is highly modified and purchased used at a good discount (at least 60% off retail). The modifications include converting the unit to triode operation, in which case the power will be reduced to around 30 watts per channel.

The choice of tubes is also critical to reach Class B performance. I advise using the EL-34 with the only alternative being the Svetlana 6550C. With all of the modifications and updates you will have an amplifier similar in quality to the Atma-Sphere with noticeably superior micro-dynamics and a richer sound, but the JA-80 is inferior in the frequency extremes. However, it can be used with a wider variety of speakers. Unfortunately, the JA-80 requires a few hours of playing music before it sounds its best, which is longer time period than any other amplifier I know.

Jadis, of course, makes other amplifiers. I’ve heard most of them. The larger ones, each with two or more chassis per channel, have the same very desirable qualities that the JA-80 posesses, but they are all too slow and veiled to be a Reference, even with extensive modifications. Their prices are astronomical as well.

The smaller one, the JA-30, is actually superior to the JP-80 in precision and high-end extension when both are equally modified, but it lacks the JA-80's power, bass extension and dynamics. It has around 15 watts in triode operation, which puts it in direct competition with the deadly Manley Retro and Neo 300B. The JA-30 is better built (hardwired), more reliable and less expensive to re-tube than either of the Manleys, but it also has a noticeable disadvantage in sonics.

This class should have around double the amount of amplifiers that are presently listed (7), since the standards of entrance obviously aren't as difficult to achieve as the top two classes. This will take some time, because I don't want to place an amplifier here and then have to remove it shortly thereafter. That would be unfair and unproductive to the readers.

The VAC is excellent amplifier that can be switched from pentode to triode. This Reference designation assumes it is in triode operation. The VAC is similar in basic sound to the Atma-sphere and JA-80. It gives up a little in midrange purity to the (lower) Class B models (where it was originally listed), but it is still outstanding from top to bottom and it can drive a wide range of speakers.

While it is possible to improve the stock VAC, it doesn’t require any "extensive" modifications. VAC has made a wide variety of excellent amplifiers for years; but these are the best value we have heard from them when considering the combination of cost (used only), power, build quality and overall sonic performance.

The best amplifiers ever made by VTL (with the possible exception of their rare and expensive direct-heated-triode models). These are real sleepers with excellent speed and detail like good solid-state amps, but they also have the natural body and richness of tube amps. Even the bass is excellent, with the right speakers. They don’t have a lot of power, only 25 watts per channel, so speaker choice is critical.

They can be improved quite a bit with modifications.
1. Changing the coupling capacitors.
2. Adding power supply shunts.
3. The feedback capacitor can probably be completely removed
4. The feedback resistor can probably also be changed (increasing the value reduces the amount of feedback.)
5. If you can get away with less power, you can even remove one push and one pull output tube per channel that are closest to the chassis. (the bias must then be changed).
Don't attempt these modifications unless you know what you are doing!

These amplifiers are far superior to others we have heard using the EL-84 output tube. Don’t be fooled by their small appearance, they sound "big". They are an incredible "tweeter amp" too. Manley Labs also has its own version of this amplifier that is supposedly even better (both in sonics and build quality), though it costs a little more. We haven't heard that model yet.

The Lumley amplifiers are manufactured and designed in England. The M-100 is now discontinued, but, as far as I know, the M-150 is still current. Both are excellent, combining power with finesse. They must be modified to reach this Class. We assume they will further improve if placed in triode operation, but we never got around to the procedure.

The M-150 has a noticeable edge in sound quality, output power and looks, but they will cost more. Both will work very well with a wide variety of speakers, but beware of dynamic speakers with either a very low impedance or poorly damped woofers. The M-150 is a particularly good match with the Martin-Logan CLS. "A poor man's Jadis."

The Rogue amplifiers are available new for around $ 2,500 per pair. They can be switched from pentode (120 watts) to triode (70 watts). They sound quite a bit better in triode operation and with no< downsides.

They are excellent performers excelling in every way, with exceptional control of woofers and superb dynamic capabilities. The passive parts are mediocre* (that's being kind), but they can be easily upgraded after the warranty expires. They are also well built for the money. This is one company that looks like it can take on the Asian tidalwave.

Their stereo amplifier (Model 88) is also an excellent value for the money, but it’s worth the extra cost to move up to their mono’s.

CAVEAT: There appears to be unit to unit variation with these amplifiers, so check them out before you commit.

* I have been recently informed by a reader that there is now a factory upgrade (The "Magnum" Series) using higher quality passive parts and that this upgrade is also "reasonably priced".

Believe it or not, the Sakura is a solid-state amplifier! It is an extremely simple design with 25 watts per channel. There are a few areas of concern.

Great care must be taken with the choice of speakers. It is best left on 24 hours a day, since it only uses 10 watts or so of power. A breakthrough, finally, in transistor electronics, and it was achieved by simplicity and proper execution, not by brute force and overkill. This amplifier is even more natural than some tube amps.

Don’t be fooled by its very tiny size, this amplifier is for real. It is overpriced though at $ 3,300 including its separate power supply. I hope someone in North America will make an equivalent amplifier, which would sell for half the price, or even less.

This company offers excellent service.

Further #1- There is also now a new 50 watt version of the Sakura, and it only costs $ 700 more. According to my associate, the 50 watt amp isn't as good, but it still may be worth the extra $ 700 if you require the extra power.

Further #2- A reader has informed me that he replaced the stock power supply of the Sakura with a pure DC battery version of it. He claims to have heard a significant improvement in sound quality. It is even possible that this battery power supply may become a commercially available product. Stay tuned.