Class 1a Featured Pick:
Clayton Audio S40 / M100 / S2000
The Clayton is objectively the most nearly perfect solid state power amp we've ever heard. Period.
That says it all, and could suffice as an entire review. But of course you'll want to know more about this incredible product.
An ideal solid state amplifier should be transparently revealing of all the musical information that the program source can deliver. The Clayton can tell us more about what our program source is delivering than any other solid state power amp.
An ideal solid state power amp should be neutral, not imposing any of its own sonic personality upon the music. When properly set up, the Clayton surpasses all other solid state power amps at disappearing, at accurately revealing the music signal contained in your recordings. In tonal balance, the Clayton sounds very neutral. It avoids the common solid state pitfalls in the sensitive upper midrange, where bipolar amps tend to sound bright, forward, and aggressive, while FET amps tend to sound recessed and politely reticent.
The Clayton is also very neutral with respect to tonal quality (essentially a hard vs. soft issue). Some other excellent solid state amps impart a consistently clear but slightly hard and analytical tonal quality to all music, while other excellent ones consistently impart a subtle (and admittedly very euphonic) liquidity to all music. The Clayton alone is able to be a true chameleon. If there is a liquid sounding nylon guitar string on the recording, the Clayton allows it to sound liquid, without adding the hard glaze or snap that is so typical of solid state sound. If there is a trumpet with brassy metallic bite, the Clayton allows it to sound biting and sharp, without softening it as some solid state amps and many tube amps do.
An ideal solid state amp should be fast, wickedly fast. As we've discussed before in previous IAR reviews, the true sonic proof of very high speed is airy delicacy, not the hard transient attack that impresses naive audiophiles. A hard treble attack, symptomatic of solid state sound, is actually a sonic sign that the amp is clogging and blocking musical information on fast transients, and therefore cannot transparently reveal music's subtle timbral inner detail that always accompanies every transient. The Clayton, like the best Electrocompaniet power amps, is so fast that music's treble transient attacks are over with before they fully register on the ear/brain. This allows these transient attacks to sound naturally airy, sweet, and delicate, while their full speed is still conveyed without fuzzy softening -- and it allows you to transparently hear and appreciate music's rich subtle inner details that occur around each transient attack.
An ideal solid state power amp should have excellent quality bass, with deep extension and tight control of the speaker, and without colored boominess or muddiness. A number of solid state power amps do well here, and the Clayton is up there among the best. An ideal solid state power amp should be dead quiet, both electrically and mechanically. The Clayton is.
The best power amps have great stereo imaging, which results not only from good channel separation (including dynamic separation via the power supply), but also from superb intrinsic transparency. Only the most transparent amplifiers can reveal the subtle hall cues that allow you to hear the depth, width, and 3D ambience that has been captured in a good stereo recording. The Clayton's superb transparency is surely a chief factor in giving this amp the outstanding imaging capability it has.
An ideal solid state power amp should sound very clean and pure, without distortion, grundge, or brittleness (which can be sign of expansive odd order distortion). The Clayton, properly set up, sounds beautifully pristine and pure, but without going overboard into sterility. And it sounds this clean even into difficult loads, and even with complex program material, and even at moderately loud levels prior to clipping. Many other power amps start sounding compressed, muddy, confused, or downright grundgy into complex loads and/or when the music gets complex. But the Clayton remains clean, pure, and transparent, doing a superb job of rendering complex music such as works for chorus and orchestra.
An ideal solid state power amp should sound dynamic, alive, and open, with an unrestricted crest factor. This is sonically important because the high momentary peaks, which live music features, help the playback of a recording to sound real. These momentary peaks are compressed in amplitude or elongated in time by lesser amps, but the Clayton plays these peaks cleanly, wide open, and with lively dynamics (provided you don't run the amp beyond its power output capability). The Clayton brings music to life very well.
The package design of the basic Clayton chassis is unusual, with great depth but very little width (the front panel is merely 9 by 9 inches on the S40 and M100). The goal of this shape is to allow the circuitry to be located within a very small space, so that lead lengths are very short. This contributes to the wickedly fast speed of the Clayton, and also to its sonic transparency. It also makes for a very compact rear panel, thereby placing the input and output connectors very close to one another. This poses a slight inconvenience during initial connection of the amp, but the Clayton sounds so good that you won't want to disconnect it (at least for several years), and thus this inconvenience is merely a minor one-time nuisance. By the way, the WBT speaker connecting posts are massive, beautifully functional units.
The entire top of the chassis is occupied by heat fins, which are necessary since the Clayton is a fully Class A design. True Class A amps can have the advantage of sounding very clean and transparent at low volume levels, and of maintaining these virtues as the music gets louder and/or more complex. This is because true Class A circuits, when well designed, have the advantage of stress imperturbability, which means that their circuit operating conditions stay almost the same, regardless of the level or complexity of the music signal (see IAR Journal 1-2 for further discussion of this).
During our evaluation of the Clayton, we discovered some factors which suggest that the Clayton's superbly revealing speed, transparency, and dynamics derive in part from a very low impedance connection of the circuitry to the powerline via the power supply. As discussed in IAR Journal 1-2 and subsequent IAR articles, any amplifier's amplifying circuitry actually functions merely as a valve, and the true source of the amplifier's output signal is from the powerline via the power supply. The amplifying circuitry that occupies the so-called signal path is merely a gate which modulates the energy that actually originates in your powerline and is delivered from the power supply.
Your powerline is actually a very fast, very low impedance source of energy. If the power supply of an amplifier raises this source impedance and/or is sluggish or blocks energy in some way, then the amplifier as a whole cannot put out energy as fast, as purely, as transparently as it should, regardless of how good the circuitry in the so-called signal path is. The Clayton seems to feature very direct access of its output terminals back to to the virtues of the powerline. In other words, the Clayton's power supply and signal path circuitry do not degrade the low impedance speed and energy delivery available from the powerline.
This direct access to the powerline's virtues in turn surely contributes to the Clayton's key sonic virtues, noted above, of superb transparency, speed, open and energetic dynamics, and clean purity. In every amplifier the energy and speed of the output originate in the powerline, and the Clayton, by having better circuitry and less circuitry between the powerline and the output, both in its power supply and in its signal processing circuit, gives you more of the energy and speed of which the powerline is capable, more of the energy and speed that music reproduction demands if it is to be lively and lifelike.
Because it is so transparent, the Clayton is very revealing of the quality of its input signal. Thus, it is very revealing of the quality of your program sources. Expect the Clayton to be honest, and don't expect it to hide flaws in your music program sources beneath a blanket of honeyed liquidity or soft fuzziness. And the Clayton is also very revealing of the quality of its other input signal, the powerline input. We found that the Clayton is more critical of the quality of the powerline cord you use than perhaps any other amp we've evaluated. With a stock generic IEC power cord (such as that included standard with the Clayton), the amp's sound has a somewhat brittle and solid state cast, much like many other excellent solid state amps. An optional premium power cord from Clayton eliminated this coloration, demonstrating that the coloration was originating in the generic power cord, not in the amp itself. A Pandora power cord (made by VansEvers) proved better yet. And, to be completely candid, the best sound of all came from an experimental lab power cord (which unfortunately does not meet UL safety standards).
Thus, for a high end thoroughbred like the Clayton, an important part of correct setup for best sound includes a premium power cord. This fussiness is not a flaw in the Clayton; rather, it is a tribute to the Clayton, and indeed is further proof of our judgement that this amp has extraordinarily revealing transparency. We want an ideal amp to be as revealing as possible, and as neutral as possible. Some other amps, e.g. those with a complex or sluggish power supply, often impose the sound of their power supply upon their output, and the amp's sonic capabilities thus often become limited by its power supply.
When the power supply itself becomes a limiting factor, then the quality of the power cord doesn't matter as much, since the power supply of the amp is the weakest link in the chain, and thus it is incapable (as is the amp as a whole) of revealing differences among power cords, or indeed of revealing much of anything else about the amp's input signals, including the music input signal as well as the powerline energy input signal. On the other hand, with a very revealing amp such as the Clayton, you'll be able to hear and appreciate differences among musical signals or performances, as well as differences among various energy sources (e.g. via various power cords) which, as you'll remember, are the true source of the amp's output. That's why the Clayton best reveals its own neutrality (e.g. being properly liquid on a guitar while also being properly biting on a trumpet) if the energy it receives from the powerline is itself neutral, and that means a neutral, fast, low impedance powerline cord.
Even though the Clayton is sensitive to and demanding of its power cord, it seems gracefully forgiving of corruption such as RFI in the powerline itself. We purposely injected RFI into our normally clean lab powerline, and the Clayton's sound did not degrade more than other amps subjected to this test. Since the Clayton started on a higher plateau than other amps, it stayed on a higher plateau, even when the powerline got dirty. Since low impedance, fast, neutral access to the powerline's energy seems so important to the Clayton's sonic superiority, we would not recommend the use of powerline conditioners in series with the Clayton, unless you have truly awful powerline hash.
As discussed above, two design aspects which contribute to the Clayton's pre-eminence are its compact size (for short, fast, pure signal paths) and its Class A operation, which requires a lot of heat fin area for the large continuous heat dissipation that Class A requires. These two design aspects obviously directly conflict. Your total heat fin area is limited if you want to keep the chassis compact for optimum speed, transparency, and purity. And if the heat fin area is limited in a pure Class A design, so also is the output power capability limited. The same basic Clayton circuit is available in several models. The S40 stereo version ($2950) puts out 40 watts per channel. The newer M100 monoblock version ($6500/pair) puts out 100 watts of mono power from each chassis, each chassis being the same optimum size package as the stereo version, and having essentially the same circuitry (but of course being devoted to putting out 100 mono watts instead of 40+40 stereo watts). The hew S2000 essentially doubles up a pair of M100 monoblocks for each channel, wired in bridged configuration, to achieve a balanced stereo amp (similar to the new McCormack DNA-500 configuration). The S2000 is easily the best bargain in the Clayton line, since it gives you essentially 4 M100 amps for just $8800, and puts out a whopping 300 watts per channel (output power is more than doubled when you bridge two amps together).
It's worth mentioning that the sound quality of the Claytons is in a whole different league from what Krell and Levinson can deliver. The Levinson and Krell products are useful comparative benchmarks because they are so highly regarded by reviewers. The Clayton sounds at least twice as good as the Levinson and Krell power amps, in virtually every important sonic aspect. The Clayton is far superior in: transparency; individuated resolution (instead of the soft smearing heard in both Levinson and Krell, especially in the trebles); articulate yet delicate speed (instead of the fuzzy dullness heard in the trebles of the Levinson and Krell); vivid and lifelike musical colors and timbres (instead of the Levinson's watered down greys); clean purity (instead of the slight sandy grundge heard in Krell); neutrality (the Clayton is so neutral that it can accurately convey the timbral extremes of music, such as the liquidity of a guitar playing alongside the metallic bite of a trumpet, while the Krell and Levinson impose their own smoothed down timbres, robbing the trumpet of some natural bite and also robbing the guitar of some liquidity). In sum, the modestly priced Claytons just stomp all over these more expensive benchmarks of the audio world.
The mighty Clayton S2000, with its 300 watts per channel, should give you all the headroom you need, for any combination of speaker, room, and music. Its powerful muscle is competitive with the large monsters from Krell, Levinson, Jeff Rowland, etc., while its sound quality is far superior, and its $8800 price is far lower. You can't ask for more than that. If your budget is more modest, we found that even the lowest powered Clayton, the 40 watt per channel S40, could fill our large reference room (30 by 25 by 14) to satisfying volume levels while driving pretty inefficient speakers. But this littlest Clayton is not suitable for shaking the walls or blasting you out of your seat. The littlest Clayton clearly lets you know when you've run out of headroom. There is a quick transition from very clean sound to quite dirty sound, an indication of the clipping that is occurring. This suggests that Clayton does not incorporate so-called soft clipping circuits (and surely deliberately so, since the mere presence of these circuits in the signal path can compromise the ultimate sonic quality which the Clayton strives for and achieves). Just back down on the volume a hair, and the beautiful clean sound returns. The Clayton does incorporate protection circuitry, to protect against untoward load or signal conditions. We verified that it works very well, and the amp simply mutes for several seconds, before clicking on again for normal operation.
The Clayton's compact chassis design helps keeps its price reasonable, since package cost in power amps is closely related to package size. And of course, in terms of ultimate sonic quality, the Claytons are true bargains, since they surpass the sonic performance of solid state power amps costing far more (those $30,000+ luxury monsters). You want a Clayton amp because it gives you insight, allowing you to hear into the texture of music better than virtually all other solid state power amps. You want a Clayton because it plays music with clearer transparency, better articulation, and more delicate finesse through the whole spectrum than any other solid state power amp. You want a Clayton because it plays music with better neutrality than any other solid state power amp, giving you liquidity from a guitar and metallic bite from a trumpet with equal ease. Insight, articulation, neutrality. That's what sets a Clayton apart from other solid state power amps, and put Clayton on a higher plateau than virtually all other solid state power amps. That's why you want a Clayton.
If your local dealer doesn't stock Clayton, you can contact them at: Clayton Audio, 8151 Stratford Ave, Clayton MO 63105 USA; phone 314-862-6017, fax 314-862-0765. Their website is: www.claytonaudio.com.
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