High current output runs in Class A mode so is able to drive even 1 ohm loads. Has peak current of 100 amps! Possess strong control over your speaker so you better have good electronics at the source. You will smile like I do but more often when you sit down to listen.

Very high cost $3,450 new but worth it if you want a stereo amp that compares to others that are twice the cost. Runs very warm if it is made to drive 1 ohm load. Just keep it away from your rack. However, does not apply with efficient speakers.

When I received the S-40 I had serious doubts about all the hoopla written in the audio press as seen on the Clayton Audio website. I was just hoping for an improvement in quality over my Denon 3300 receiver. Since I had sold the receiver, I anxiously visited a friend whose system included the Sony SCD-1, Rowland Monoblocks 6's (over $12,000 value) and with the Avalon Eclipse. With the Rowland Consummate preamp we sat down to listen. After a half hour cold start the music was slow in forming but in no time something good began to take shape. The power of the amp was sufficient enough to drive the 87db inefficient Avalons to satisfactory levels. But the gain was preventing the sound from opening up. After adjusting the gain on the Rowland the Clayton was simply "magic". There was a tube sweetness from the midrange and lots of bass impact and control. The soundstage was "huge" and a quiet stillness was immediately noticable. My friend was very impressed with the drop in noise level. Now consider why this is significant. The Rowlands were running in balanced mode while the Clayton S-40 was not! Balanced is inherently quieter than unbalanced I used to say. The Clayton S-40 is a music listeners dream amp since it exemplifies grace under fire (hard rock music, complex orchestral works) presenting no loss of control or sense of compression. The sound simply boogies with the best and on this night embarassed the Rowlands. Highly recommended if you are looking for a single stereo amp above the norm. This is a quiet gem that must be heard. If you see one on the net used, grab it.

Similar Products Used:

Vtl 225, Rowland 6's...

Natural tube-smooth sound with solid-state drive and current capability

Not a status-symbol, no snob-appeal.

I concur to all the other reviewers' opinion. This is one of the most under-rated amplifier and best-kept secret. In addition, the 70W rating is very conservative, because M70 is a current-centric design that can pump out 100Amp of peak current, essentially drives any difficult load. It benefits from a good power cord upgrade, and possibly an amp rack or maple pasta board below it (lift it off the carpet). Before owning M70, I used Mark Levinson 23.5, and found the ML 333 or Krell, at that time not as good as M70 in conveying the sense of music truth, or as fine and delicate sounding.

Similar Products Used:

Mark Levinson 23.5, Audio Research Classic 30, Classe DR-2.

clarity - the ability to discern the smallest musical details; wide, deep soundstage produced; build-quality

must be used with reasonably sensitive speakers for best results

This is a class A 50 watt/ch (into 8 ohm loads) amplifier with beautiful detailed sound quality. After hooking it up and breaking it in for several days, the first thing I noticed was the width and depth of the soundstage produced. The second thing I noticed was how detailed the sound was; you are able to, for instance, tell precisely how a cymbal is being played. For me, a piece of equipment's ability to help me "hear into the music" is what makes that equipment so unique and special. The Clayton S-40 is very unique and special.

I also own a Krell KAV 250a, which I use more for home theatre. The Krell can play louder, but is flatter and more 2-dimensional sounding. It is an excellent amp also, however.

Similar Products Used:

Krell KAV250a

Only lacking in that last bit of nirvana midrange that can be found on amps like the Cary 805c ($9000)

[This is a review for the M-100 not the M-70, please pardon its length but I feel these babies warrant a thorough evaluation]

The Claytons are astoundingly superb amplifiers. I have compared them to many far more expensive amps such as the Cary Audio 805c and come away wanting the Claytons instead. The 805c's have an ever so subtly more refined midrange (Cary's midrange is the best around if you ask me) but it's not worth another $2500 especially since the bass isn't as well defined as on the Claytons. The 805c's are the only amps I've heard, other than perhaps the Manleys (which are more expensive than the Claytons and put out a mere 11 wpc.) which even approach the sound of the M-100's.

The M-100's sound like tubes in all the ways you want. They have that natural, non-fatiguing, palpable sound tube junkies just love. They are smooth and elegant just like the finest single ended triode amplifiers. But like the best solid state amps they have very well defined bass which pushes them out in front of even the very best tube amps I've heard.

The build quality is exceptional. Talk about overbuild - if you have had a chance to open these puppies up (be careful because if you don't know what you're doing you'll have trouble putting Humpty Dumpty back together again!) you will understand what I'm talking about. The quality of the components used inside is simply the best available, and many of the stuff used is new to the world of consumer audio. These are superbly constructed units with unusual attention to detail. A light on the back to remind you that the unit is still powered up when you go to unplug speakers or inputs, feet on the back to protect the WBT binding posts, the plywood lined crates they are shipped in, etc. These guys know what they are doing. My discussions with Wilson Shen, the head honcho and designer at Clayton, have been very informative and pleasant. The company provides excellent support and information.

The manual is short but adequate. It has all the specs you need and explains the bias switch and all the rear panel information. That information aside, the amp is entirely self explanatory and maintenance free.

People who complain about the power rating either haven't tried the amps or are just plain stupid. These are current based amplifiers which means you can drive Maggies with the S-40 (read the reviews folks) which is unheard of. Driving electrostats with 40 wpc.? I don't think you'll be running out of power with the M-100s unless you have huge electrostats, a room the size of Notre Dame, and like to bleed from the ears regularly. These amps play loud, and never lose their grace even at deafening levels. Class A beyond their continuous power rating. Now that's impressive!

What I love about Single Ended Triode tubes is that, as Sam Tellig says, they bring you closer to the music. You feel like you have either removed a component from your chain, or in less technical terms like a string quartet just sat down in your living room and started to play. And what I love about tubes in general is that there is no listening fatigue. No harshness or graininess to the sound. You get more natural sound. In short - I like tubes and SET amps for the same reason I like vinyl: it sounds more like music rather than the reproduction of music.

The Claytons enhance the listening experience to virtually the same extent, and in the same ways, as SET, tubes, and vinyl. But they do it without the shortcomings often associated. For one thing the bass is better than with tubes, for another the M-100's provide much more power than SET amps. They are much more compatible with speakers than their tubed SET cousins which are fussy both in terms of sensitivity and more importantly in terms of impedance curves. The Clayton will handle more demanding loads because of its current based design. And you don't have to take out a second mortgage to roll your tubes every three years.

The bottom line is that the Claytons make beautiful music. They dissappear into your system and that's the best you can ask for from an amplifier. They also help your speakers disappear into the music, which is a wonderful trick. They don't sound like tubes, they don't sound like solid state: they sound like violins, pianos, drums, basses, etc. They put music into your living room and make you forget that you are listening to a hi-fi.

Sure $6500 ain't cheap, but for the money there is nothing out there that compares. And I've now heard several amps that are much more expensive (the Cary 805c's are $9k) and while they sound fabulous, I like my Claytons better for the money. I am excited to hear Clayton's upcoming pre-amp, the P-2000, and also their new fully balanced designs, the S-2000 and M-2000.

So - they get five stars for value because they are, exactly as the popup menu says, "Giant killers" in every sense of the word. Forget Levinson and Krell, Clayton is where it's at. In absolute terms they may be expensive but in relative terms they are the deal of the century. Performance is a no brainer: I'd give them more than five stars if I could. I can't say enough good things about these amps. I've been looking for the ultimate SET tube amp and I never thought I'd end up with a solid state unit, but life is full of surprises I guess.

Any questions, or if you want to know where to buy Clayton amps, email me at evan@sover.net.

Similar Products Used:

Cary 300SE Signature, Manley Neo-Classique, Cary 805c, several solid state units

My system:
Cary SLP-94 pre-amp
Cary PH301 phono pre
Clayton M-100 amplifiers
Joseph Audio RM30si speakers
VPI TNT Mk III turntable with flywheel and SDS
VPI JMW 12" tonearm
Grado Reference cartridge
Straight Wire Maestro II cable throughout

transparent midrange, solid bass, enormous power, incredible value

none

This review is for the S-40, not the M-70. I have requested a review category for the S-40, but none provided yet.

The S-40 is the stereo version of the M-70 monoblock housed in a single M-70 chassis. In Doug Blackburn's Soundstage review, he wrote: "The S-40 is the virtual sonic duplicate of the $5,600/pr M-70 monoblocks."

I have gone through more amps than I want to admit. My current reference and favorite amp is the Audio Research VT100 MkII. The S-40 is as good (better in some ways) as the AR, and definitely better than any solid state amp I have ever experienced.

I cannot point out any single weakness. Driving my Dunlavy SCIV-a or my new Taylo Reference Monitors, they produce music in a way that will lock you in your chair far beyond the time that your wife wants you to be there.

Maybe it's because it runs in pure class A, or maybe it's the power supply, but whatever innovations the designers of this amp have created, the sound is wonderfully pure and grainless. For those of you who can relate to the existence of a basic harmonic difference in the quality of sound between tube and solid state, the Clayton captures the harmonic richness of great tube gear, but at the same time does not color the signal source. The overall result is a nicely layered 3 dimensional rendering of the music with great clarity, speed, and bass punch.

Keep in mind that I'm talking about the S-40, which is supposed to be 40wpc. I don't beleive for a second! As I said, I've owned several high-powered pieces, including a 275wpc. None have demonstrated the power of this Clayton. It has the most rock-solid bass and ability to play loudly without strain of any amp I have ever used!

And the build quality is just as good as the sonics! It is also good to know that the amp is made in the US with excellent product support. This has been an important lesson for me after experiencing the frustrations that can be had when dealing with a product that is only provided through an importer.

If you are looking for a high quality amp in the $6K+ area or less, this baby can be had for less than half - maybe a lot less. But don't let the price or the 40wpc fool you. This amp is a giant killer, and deserves to keep company with only the best components.

Similar Products Used:

Electrocompaniet AW250, McCormack DNA 2.0 Deluxe, Threshold T200, Audio Research VT100 MkII

I have had many different amps in here within the last 3 years...the Clayton M-70 monoblocks are really the most musical amps I have ever heard...they just get out of the way...and let me enjoy the recordings. I am using the DH Labs BL-1 interconnects and the biwired version of the Silver Sonic T-14 speaker cables. My CD player is the nice sounding Rega Planet and my turntable is a VPI with a Grado MM Reference. The preamp I now have has a great sounding phono section!
The M-70s have power to spare, drive even my SL-3s and Merlin VSMs without effort.

I recently was able to buy a new Hovland HP100 preamp (tubed)...and the images are more holographic, palpable then ever and I listen to LPs and CDs all the way through as if I had never heard the recording ever before! Dynamic, effortless, elegant, extended, and powerful. The HP-100 and the Clayton are beautiful together. The Clayton is truely the first amp(s) that I can say are tonally correct. (I teach piano!)

Roni

What else can be said about a great product, I've never read a bad review on the M 70's and there are several out there. Check out Soundstage, Positive Feedback or the Clayton Website. Highly recommended!!!!! They match well with the Von Schweikert VR 4's , DH Labs, Kora(French Tube)Preamp,CAL Audio. Anything I say is Absolutely redundant.....Buy Em!!

I love these amps. They have a beautiful, natural sound. Very smooth, very clear. Much more tubelike than almost any solid state amp, but without loosing bass, highs, or any detail. Detail is superb, imaging is precise. Fairly open sound. A great mix of the best of tube and SS attributes. I'm auditioning expensive new speakers right now, and these babies go with me to every dealer. So far they have sounded better than the Classe 301 and the CJ 250 solid state amps. I got my M-70s 2nd hand off the 'net, and sent them back to the factory for a check over. Terry Rossen at Clayton Audio was very helpful, and got them back to me in factory perfect condition in just 2 weeks, updated for a very fair price. It was painful to listen to my old Acurus A200 (see review) while they were in the shop! I have not played them at Turn-that-damn-thing-down! volumes, so I can't speak about clipping. But at ordinary to rather loud levels there is no sign of this, or any evidence of the "mid-fi" spoken about in another review here. If it turns out that they can't drive low efficiency speakers well, I would either find other speakers or buy another pair of M-70s and bi-amp. With the 86dB/4ohm Aerial 10Ts the sound was fantastic and unstrained. This weekend, 91dB/5ohm Dunlavy IV/a .

The following is an excerpt from a formal independent review that I did two years ago and for which I own full rights. I hope it is of value to the Audio Review crowd.
The Clayton amps combine the musicality of tubes with the dynamics and robust bass of solid-state. The amps' design itself is unusual, and the engineering methodology that produced it turns out to be as surprising as the resulting sound is appealing.

Clayton Audio, named for a suburb of St. Louis, Missouri, is the creation of a pair of audiophiles: Wilson Shen, an electrical engineer retired from IBM, where he specialized in power supply design; and John Nye, an economics professor. Before joining with John to create Clayton Audio, Wilson had been an amateur audio experimenter for years, building amps for himself and friends. John supplies the golden ears of the team. His sixth-row season tickets to the St. Louis Symphony keep the ears "tuned" up.

What we have is a couple of very bright guys with no specialized training in audio electronics. As I went back to Wilson and John several times over the course of my evaluation, I began to believe that their lack of training in traditional approaches to amplifier design might have a lot to do with why the Clayton monoblocks lack traditional solid-state sound. The most important thing to understand about the origins of the Clayton amps and their technical characteristics is not what Wilson Shen did, but what he didn't do. To appreciate that, you have to start with an understanding of class A operation and some of its benefits.

Class A operation requires biasing the output transistors to maintain a positive current while following the ups and downs of the signal. In class AB operation, strong signals make individual transistors "bottom out" with the signal being crossed over, back-and-forth, between companion transistors in push-pull pairs. (The Claytons have four push-pull pairs of output transistors in each amp.) In addition to avoiding any imprecision in the cross-over process, class A can avoid non-linearities that creep in near the "bottoming out" point.

Increasing negative feedback can correct for all of the cross-over related distortion in well-designed class AB amps, but many designers believe that wrapping negative feedback around a circuit is more like applying a Band-Aid to treat the symptom than curing the cause. In fact, manufacturers have often succumbed to excessive use of negative feedback in order to reduce total harmonic distortion (THD) to absurdly low levels and make power amps "look good on paper." While excessive negative feedback can also solidify bass, it can create the nasty, etched quality associated with mid-fi solid-state sound. As overdoses of negative feedback are increased in an otherwise weak design, the cymbals player in the back of the orchestra can leave his seat, advance to the front, and end up in yo' face. Worst case, he throws away the cymbals and enlists an army of little men with pressurized air hoses -- the kind you use to fill your tires. When they punch the valve buttons in unison you get the nasty, high-pitched hiss that has made all true audiophiles cover their ears and retreat rapidly from car stereo displays at discount stores around the globe!

Whether Wilson Shen meant to or not, he really broke with the tradition of trading off negative feedback against THD. I knew something was strange when I saw no listing for THD anywhere in the Clayton Audio literature. I called Wilson and asked him about specs for THD, global negative feedback, and slew rate. He didn't know any of these! Wilson Shen doesn't even own a distortion meter! (Hear the collective gasp from the audio engineers in the audience?) Wilson looked at his output transistors' characteristic curves and biased in class A for linearity. (Most so-called "class A" amps cross over into class AB mode long before they reach rated output. The Claytons could go 10 watts beyond their rated 70 and still be in class A.) Based on this highly linear operation, Wilson applied just enough negative feedback for stability. He says it is somewhere below 10 dB.

Even though I personally own several pieces of audio diagnostic equipment, I don't need meters, measurements, and math to tell me how something sounds. Put another way, if a tree falls in the woods and there is nothing there except a microphone, meters, and an oscilloscope, there is no sound! Even so,I wouldn't have the nerve to go into production on even a pure class A amp without checking the THD. Conversely, if you've heard harsh, piercing sound from a power amp with 0.001 percent THD and wondered what the sound would be like if we took away the designers' distortion analyzers, here's your chance to find out!

While class A operation can allow much lower negative feedback, it imposes an obvious disadvantage to the consumer: biasing the output devices so that they always produce enough current to stay in class A up to full rated power causes them to work as hard, on average, as they would at full power. This takes a toll on your electric bill;, makes them run hot, requiring expensive heat sinks, and puts extra mileage on the output transistors. The Clayton amps offer a switch on the front panel that allows you to go to "low bias," which keeps them in class A only up to 40 watts of output. You can use this setting as a standby mode, since throwing the switch can be done with the amps on and produces not so much as a click from the speakers.

The yearly electrical cost of leaving the amps on full-time (200 watts each at high bias) amounts to a few percent of the initial purchase cost. The low-bias mode reduces the electrical cost by only 25 percent. My calculations indicate that the output transistors are loafing at idle, even on the high-bias setting, so I believe John Nye when he says they've had a pair of amps playing non-stop for over a year with no degradation in performance. The biggest advantages of the low-bias mode may be the cooler operating temperature that adds less unwanted heat to a room and is less likely to burn fingers.

The first time I turned the amps on, I had never heard a Clayton Audio product, never talked to the owners of the company, and never read a word about the opinions of others. I just threw on a few of my favorite CDs and listened.

I began with my all-time favorite piano piece: Ivan Moravec plays Beethoven, Volume 2 (VAI Audio, VAIA 1069). Though I only wanted to quickly sample the piano sound, once I started, I could hardly tear myself away. Piano timbres were both accurate and natural, with that sense of immediate presence that makes us yearn to hear more. Based on piano music, if I graded the Clayton amps across the litany of the latest equipment-reviewer clichés for the manifestations of dynamics, they would receive As in all categories from "speed" to "sense of pace." Transient attack is superb. You get both the power and the nuance of the concert grand: mids and highs ranging from the staccato to a light, airy, ethereal delicacy; and lower registers that can hit hard with clean, percussive authority, roll like distant thunder, or provide subtle harmony to the melody. The Claytons moved me closer than ever towards feeling the presence of that nine-foot sounding board in my listening room!

Next, I tried my all-time favorite jazz instrumental for sonics: the Classic Records vinyl reissue of Dave Brubeck's Time Out (CS 8192). Again, the amps were in their element. Images were tightly focused in a soundstage of expansive depth, breadth, and height. Image focus was not at the expense of hardness, grain, or harshness; there was no unnatural etched quality to the images or to the sound. The Claytons reminded me of my first drive in a Porsche 911, when I had the sensation of handling the curves with that essential feel of the road, yet no harshness in the ride.

With all this promise of speed and acceleration, why not give them a go on a real drag strip? A few trials on selections from Reference Recordings and Pope Music on a variety of speaker loads ought to do it. It was here that I found some real limitations. The more challenging dynamics, played at high volume through more difficult speaker loads, brought a mid-fi sound to the Claytons. Transparency, detail resolution, and bass definition all suffered before outright clipping set in against the tougher speaker loads. Within their comfortable operating range, however, they have great dynamics that include solid, accurate bass. More akin to sport coupes than muscle cars and unlike the GTO of lore, they are better on the road course than the quarter mile.

On male vocals, classical, jazz, blues, and pop, the Claytons did a superb job across the board with all speakers used. For example, on the vocals in Blue Rodeo's Five Days in July CD (Discovery 77013), the amps stood out both in the natural rendering of voice and in sound-stage depth as compared to various other amps, tube and solid-state, that I had available for comparison.

As a challenge for smoothness on the highs, I turned to Kendra Shank's Afterglow CD (Mapleshade 2132), which, in spite of a few instances of tape overload, seems headed towards status as an audiophile classic. (Check out Kendra's web site at www.speakeasy.org/nwjazz/kendra.) My first observation on this CD was the wider soundstage presented by the Clayton amps. On track two, they placed the tinkling wind chimes several feet further outside the speakers than various reference amps, including a Sunfire and a pair of Cary 300SE monoblocks. I found myself noticing more details too, like the sound of the piano pedal on the first cut. Imaging and detail rendering aside, however, female jazz vocals like this pointed up what was, for me, the only slight negative in the sound: I would prefer a somewhat more liquid rendition.

On jazz and pop female vocals, you may prefer more tube-like highs to the highs of the Clayton amps. This preference will be dependent on the characteristics of other elements of the system as well as on your personal taste. In general, the Claytons' sound on the highs, while lacking in grain, hardness, or harshness, is not what I would call sweet.

I reinforced this one potentially negative finding on a variety of what I considered to be challenging female jazz vocals on vinyl as well as CD and on multiple combinations of preamps and digital front ends. Finally, I discussed the issue with John Nye. He pointed out that he had voiced the amps on strictly classical materials, including vocals. He believes that jazz and pop vocals, which tend to be very close-miked, can start out with an unnatural sound and, therefore, don't make sense for use as a reference for voicing. In his defense, I noted that female vocals from classical selections were satisfyingly natural. The "problem" with the Claytons may well just be "telling it like it is."

The sound of the Clayton monoblocks is matched by their excellent fit and finish. The only gold plating is where it counts: on the premium WBT binding posts and single-ended input jacks. (While the amps offer balanced inputs, only the single-ended inputs were used in this evaluation.) LEDs on the front indicate the selectable bias status, and a nifty LED on the back warns when power is on at the speaker terminals. Opening the outer casing reveals a 700 VA torroidal power transformer and two 50,000 microfarad power-supply capacitors, which are the size of beer cans. The internal build quality further reinforces the pervasive sense of attention to detail.

I would personally be comfortable with the Clayton monoblocks as my own reference. They have tight, solid bass, coupled with a world-class, tube-like midrange that is as good as I've heard on acoustical instrumentals. Contrasted with tubes, which can be had for similar dollars per watt, they offer better bass, better dynamics at this power rating, as good or better midrange, and highs that favor detail over the liquidity offered by some tube designs. In tubese, they are more like 6550s than EL-34s. As good as the Claytons are, however, they deteriorate rapidly to a mid-fi sound when pushed near their power and/or load limits. They will match up well with most speakers of 88 dB or better efficiency if impedances stay above 6 ohms across the audible spectrum. Load complexity also plays a role, so if your speakers of choice falls near or lower than either of these specs, you should insist on finding a way to try the amps with your speakers, on your kind of music, before you buy (which, of course, we should all try to do anyway when purchasing power amplifiers).

In summary, the Claytons live in a domain that is somewhat confined by speaker sensitivity and load characteristics. Just how good are they in their domain? My listening tests said that if they don't own their domain outright, they are at least co-owners! If you're looking for power amps in this price range or higher that combine most of the best of both tubes and solid-state, you've got to find a way to hear the Clayton monoblocks.

MANUFACTURER
CLAYTON AUDIO
8151 Stratford Avenue
Clayton, MO 63105
U.S.A
Tel: 314-862-6017
Fax: 314-862-0765

Price: $4800 per pair
Warranty: 3 years
Serial Number: M01131/M01132

SPECIFICATIONS
Power Rating: 70 watts continuous into 8 ohms
Input Impedance: 47 K ohms
Voltage gain: 26 dB
Power consumption (each):
150 watts in low bias mode
200 watts in high bias mode
Heat sink capacity: 0.13 degrees C/watt
Dimensions: 9.25"W x 20"D x 9"H
Weight: 40 pounds each

ASSOCIATED EQUIPMENT
Digital Front End: Cal Audio Icon Mark II HDCD player, Ultra Analog dual 20-bit HDCD (prototype) DAC, G & D Transforms transport, JVC XL-Z1050 CD player.
Analog Front End: Benz Micro Glider Cartridge, Series 20 (medium-weight carbon fiber) tone arm and head shell, Kenwood KD-500 turntable.
Preamplification: Cary SLP-94, Sonic Frontiers SFL-1
Amplification: Cary 300SE monoblocks with two optional SE Power Banks; Sunfire stereo power amp (used Lab inputs and both current source and voltage source outputs)
Speakers: Infinity Compositions, Model P-FR (96dB @ 2.83 V and 1 m, 6 ohm); Sound Dynamics 300Ti (87dB @ 1 w and 1 m, 6 ohm); Newform Research R8-1 (88dB @ 1w and 1 m, 8 ohm)
Speaker Cable: Audioquest Midnight II
Interconnect: MIT MI Terminator 2; MIT MI-330 Plus, Series Two; Tara Labs RSC; Tara Labs Quantum IV; custom digital interconnect

ACCESSORIES
Isobearing 3.3 Vibration Damping Support Globes

Realistic portrayal of acoustic instruments and voices. Dynamics are first rate. Extremely resolving and involving. Near perfect tonal balance.

As close to an "ideal" amplifier as I have heard within its its useful opetating range. A few more watts is all anyone could ever hope to ask for.

The M70 is the most natural and realistic sounding amplifier I have ever had in my system. Period.

Similar Products Used:

Levinson 23, 27, ARC Classic 60, Sunfire Signature, Pass Aleph 5.