Class D Ncore Atsah in the house

I am currently trying out a pair of Class D Ncore NC1200 Acoustic Imagery Atsah monoblocks.

I inserted the Atsah amps in the position typically occupied by the Clayton M300 amps shown in my virtual system. There is nothing "wrong" with the Claytons, which sound fantastic. My experience has been that, in the range of high-powered SS amps, it would be hard to top the sound of the Claytons that output 300/600 wpc into 8/4 ohms, all in Class A. About a year ago a pair of the new 500 wpc Cary monoblocks I tried couldn't even come close. I have simply had an urge to try other amplifier options and couldn't pass up an opportunity to try out these Acoustic Imagery Atsah amps.

I will cut to the chase and say that I wouldn't have wasted my time with this thread had the amps not sounded good right out of the box, but they did! I will post some observations during the course of my audition and this thread will give others who have tried, or who own, various versions of the Ncore amps a chance to weigh in.

Some system stuff not posted is that with my Mac mini computer source, music files currently consist of ripped CDs using XLD and played back through Pure Music running 24 bit with Memory Play and Upsampling only multiples of 2 and limited to 88.2 kHz. I have tried a higher upsampling limit of 176.4 kHz and that sounds good too, but for now I am currently using the lower limit. Before I finish the audition, I will also try the amps using my MUSE Erato II disc player as a source.

The amps showed up stone cold (Michigan, eh) and very nicely packed in a single hard shell SKB (Pelican-style) case with dense foam padding. I sat them on top of my Claytons to make cable runs and down-the-road direct comparisons easier. They are sitting on the stock feet, on a one inch thick oak board, which is supported on hard rubber feet above the Clayton M300s. The Claytons sit on Sound Anchor amp stands spiked to the concrete floor with brass Audiopoints. The Atsah stock feet look like small-medium sized rubber feet inside of which someone has placed a small rubber ball. These are the same feet shown on pages 2 and 3 of the 6moons review, but not the spikes shown on the amp in the stacked position. I doubt the solid milled aluminum chassis needs damping but just for kicks I have placed a single brass weight (edenSound Solid Brass Damping Weights that come with EAR elastomer backing) on the top of each amp. I am using Furutech FP Alpha 3 power cables with Oyaide P-079 plugs and DIY XLR ICs made from either VH Audio OCC copper with AirLok insulation (made per the fine silver IC recipe) or braided high purity (6Ns) copper in cotton wire from Jupiter Condenser, both shielded designs, and both with Furutech FP-601/602G connectors.

After the amps warmed up for a day, I decided to try a couple of things. The inside pictures of the Atsah amps from the 6moons review show two positive and two negative output wires coming from the Ncore board to the four binding posts, one wire to each post. Most amps with bi-wire posts run a single pair of output wires and then jump to the second pair of posts. My bi-wired HT Pro 9+ speaker cables are joined at the amp end so I only use a single pair of binding posts per amp. Since I own a nice set of PCOCC wire jumpers with spades on one end and bananas on the other, I hooked them up to connect the unused pair of posts on each amp with the pair of binding posts that I have my speaker cables connected to (thereby "jumping" the amp binding posts). The result may be a jedi mind trick but I believe the dynamics may have improved a touch, or, maybe the amps were just more warmed up. Either way, I will leave the jumpers connected for my audition period. I also have an EVS ground enhancer connected to the negative post of each amp.

After listening to the amps playing through my custom SMc Audio preamp for awhile, I decided to try them with a Goldpoint discrete resistor passive volume controller. I have read reviews speaking of the (perceived) virtues of running Ncore amps directly from the volume control of certain DACs. The relatively high input impedance of the Ncore amps (between 90 - 100K ohms) should be conducive to getting good results with passive controls. In my case, the results using the Goldpoint control were the same as with my Clayton amps. The sound was quite "pure" at first but as I played more tunes there seemed to be a little something missing. Reinserting my SMc preamp resulted in an immediate increase in tone density, body and drive, with no penalties in the areas of detail or purity. I have found the SMc Audio preamp to offer truly excellent sound (compared to over 20 other expensive preamps I have had in my system) and so it will remain in use for the remainder of my audition of the Atsahs.

My only other functional observations at this time are that the amps have gotten moderately warm and that the binding post layout is different from the reviews I have seen. Regarding warmth, they are nowhere near as warm as the Claytons in Class A but the Atsahs are certainly warm to the touch and warmer than you would think from reading the Ncore literature and amp reviews. The heat is mostly on the top of the chassis and somewhat on the bottom but not so much on the sides. I suspect this is simply the milled aluminum chassis doing its job as a giant heatsink, but it may be a consideration for folks planning to put these in an enclosed cabinet. It was a pleasant surprise that the binding post layout had a single negative and a single positive post on each horizontal level, rather than the pairs being stacked vertically as shown in the pictures from the 6moons review. This allows the speaker cables to be hung off the back in a normal fashion rather than being required to run in from the sides and straddle either the power cable or the interconnect cable. I think an optimal set up would be to have the pos/neg pairs horizontal as they are on the amps I have, but to space and stagger them like this:

Ok, how do they sound? These sounded pretty darn good stone cold right out of the box. They are absolutely the point you need to look for the cool blue light under each amp to tell if they are turned on! I could tell right away they were contenders. I predict at the end of my time with them, if I find any shortcomings compared to the Claytons, they will be errors of ommision rather than commission. I am pretty sensitive to gear that doesn't sound "right" in some way, dry, harsh, sterile, tipped up, lacking in tone density, flat, etc. etc. These amps displayed none of those faults and have sounded better and better over the 2 days they have been turned on and playing in my system although I believe the overall burn-in has occurred previously since they are demos).

The bass from these amps is very good but not overdone. Think full, plump, defined and deep, with very good dynamics you can feel when the music demands. The excellent sound continues up the frequency range and is overall even-handed, with no evidence of discontinuities between ranges. Tone density has come on nicely as they have warmed up and dimensionality is also good. They do not provide the expansive soundstage offered by some tubed gear but in my system, and to my ears, everything is as it should be, and surprisingly similar to the Claytons in that respect. I suspect these amps may not "wow" listeners upon first hearing them, but will be valued for their realistic portrayal of the music over the long haul.

The treble seems just a touch shelved down and may not be as "sparkly" as some would wish for. The detail all seems to be there but, compared to the midrange and bass, the treble could be just a touch more prominent. This characteristic should actually be helpful in making poor recordings sound good. One thing I will try is to increase the upsampling in Pure Music to 176.4 kHz, which sometimes has the effect of increasing treble or shifting the frequency slightly upward. This treble observation is subtle and is NOT a major issue with me and IN NO WAY detracts from how good these amps sound in my system. I suspect, if there are any deficiencies compared to my Claytons they may be related to ultimate tonal saturation, which is excellent through the Class A Claytons. However, that is for another post since, for now, I am going to continue listening to these excellent sounding amps.
Nice post Mitch2. Thanks for taking the time to review the Atsahs.
Thanks for the detailed impressions Mitch2, really appreciate when people take time to write what they feel about the gear.

Hopefully more people start using the NC1200's on their rigs.
No problem, SES, I have enjoyed this. I am listening to Warren Haynes Live at Bonnaroo right now, Tastes Like Wine and now Wasted Time, his guitar just rings - attack, sustain, decay just the way it should be. Vocals have body, and the crowd and other ambient venue background stuff is believable. This is not complex music but through these amps it just sounds "right." I rocked out with them a bit earlier today when I had the house to myself for awhile and they were rock steady, Los Lobos, Rolling Stones, Stevie Ray, just couldn't shake them, turn it up and guess just gets louder and, if anything, sounds better.

Ergonomically, these are just so cool, with their compact size, chunky solid build, the ability to leave them turned on all the time, blue street rod chassis lights, and that dead quiet background. The simplicity of use is off the charts - just ignore them, hit play

I am about halfway through the audition and plan to do some A-B comparisons with the Claytons this weekend. It will be interesting to see how that goes. I suspect folks who purchase these are after a complete package and appreciate the sum of their attributes. If you leave your audiophile hat off, and listen for enjoyment, most would likely want for nothing more. Not that they do anything wrong, because they really don't, but I do hear a couple of little things that will be interesting to check out when the Claytons go back in. However that goes, it will not take away from the musicality these Atsah amps have displayed and the enjoyment I have had listening to them.
I am surprised at the lack of interest in this topic of the Ncore NC1200 Atsah amplifiers. There is a lot to like.

I am on the last two days of my audition and put the Clayton amps back in my system for a bit last night. My first take is the Claytons are sweeter in the high frequencies, with better decay, display better tonal density and are a little more vibrant sounding. The Atsah amps sounded just a tiny bit dry in comparison but had tighter, punchier bass while the Clayton's bass was fuller and not quite as well damped. The Atsah amps are quieter, since they make no noise until music is playing but the Claytons come alive sooner at lower volumes.
Interesting. I gave up my M-300's for Atsah's. In the end, I couldn't be happier.

Enjoy your M-300's, they are fantastic Class A amps!
I own a pair of NC1200 mono amps which I got at a terrific price. Unfortunately, the cost of current NC1200 amps puts them out of reach for many folks. $12,000?! Too bad. Fortunately, you can get a lot of the way there with an NC400 amp at $2000, assembled yourself.

As to the amps, I have used Hypex UCD and NC400 modules and believe the NC1200 to be the best amps I've ever heard. I have an Aesthetix Janus tubed preamp and the synergy is wonderful driving my very inefficient speakers.
Spent more time listening and switching in/out between the Claytons and Atsahs this weekend since I am on the last day(s) of the audition.

There is a lot to consider, and I like the Atsah amps quite a bit. I took notes and plan to summarize my thoughts more completely in a review format, with some comparison notes between the two amps.

Bottom line for me is the Atsah amps are very musical and enjoyable to listen to, with highlights being very good tonal density, an involving midrange, and excellent bass. In my system, based on sonics alone, I liked the Claytons better, because of their sweeter, more proportional high frequencies, and slightly better harmonic development at all frequencies, at least to my ears. However, the Atsahs offer other benefits by being dead quiet, easier to use since they can remain powered up and ready to go all the time, and visually cool with their small, chunky, solid case that I like better than any of the other NC1200 amp cases I have seen so far. If you factor in the whole package, I rate this a coin toss, with the winner depending on what attributes a prospective owner values most.

Jtwrace, I certainly understand the attraction, and I appreciate how you could choose to keep them over the Claytons.

I too, could own these amps and be happy with both how they sound and how easy they are to use.

The ATSAH's are still $8995 from Tweek Geek.
Mich2, the NC1200 amps need a lot of hours on them before they will sound their best. Also some power cords work better then others with them. Also turning them on and off does not help. Once off for any period of time they will require a day or so before the will come back to were they where before they whore turned off.

IMHO they need at least three weeks of continuous play for them to show there stuff and will improve further for another like amount of time. Do not misunderstand me, they will sound dam good around 100 hours but not as good as they can sound.

I am basing this that all NC1200 will need the same burn in. Maybe not.

Also I wonder what sonic differences will there be between the different NC1200 that are and will be out.

I know from experience that the NC400 DIY amp, as good as it sounds, is not in the same league as the NC1200 amp.
Hifial, I appreciate the comments. Sadly, the Atsah amps are now back on the road to their next stop. I did have some time to make a few cable changes, but did not have the time to get to know the amps as I would if I owned them. I can say the pair I used should have had many hours on them and remained powered up the entire 11 days I had them. I did not hear improvements after about the first full day. They did get a little warmer than I expected, especially when playing music for awhile but, after using exclusively Class A amps (Claytons and Lamm) over the past 5-6 years, I actually appreciated that they ran a little warm.

I have never heard NC400 amps but directly compared the Atsahs to a pair of $17K Class A monos that some have ranked among the top solid state amps you can purchase - and the Atsahs compared very favorably. The comments that I make in my previous posts above, about their high frequency performance, characterize quite subtle sonic differences that I heard between the Atsahs and my Clayton amps,but certainly do not imply I found the Astahs to be anything less than very nice sounding amps that are enjoyable to listen to over a wide range of music. I believe I could own them and be quite satisfied with the music they make. Again, their small size, absolute stone dead quietness, and ability to remain powered up all the time are very attractive features to me.

If I did own a pair, I would probably try different cables, footers, damping and stands, and maybe even experiment with wiring, binding posts and fuses also. However, those items seem pretty well thought-out on the stock amps so really I think you can get 99% of the way there by simply hooking up your favorite cables, powering up and enjoying the music.
I deducted your final comments since line 1. Thanks for sharing it.
Anything new on these....?
There was a lot of initial noise, and some good reviews, but other than an occasional mention of Merrill, I haven't seen much on the Hypex Ncore NC1200 amps lately, from new or existing owners, reviewers, Hypex, or amp manufacturers. Are the owners just quiet or not many buyers?
I've used various switching amplifiers since PS Audio introduced the $1500. HCA-2. The HCA-2 forced me to upgrade my homes VAC which turned out to improve everything not just audio and video.

Until recently, switching amplifiers have remained reasonably priced. I was able to sell my NuForce version 3 9SEs and purchase the nCore 400 kits with 1K left over. I don't doubt for a minute that this latest generation, I'll call 1200s, can be an improvement in performance.

Even so, I'm having a hard time understanding the phenomenal increase in cost. Obviously more robust power supplies, upgraded switching modules, I/O sections, and even stupidly exotic casework, will increase costs. But is it really a 10k improvement? Even with trying to keep that subjective audio aspect in my head I just can't get my arms around the cost without feeling taken advantage of? Unless, of course, class D has finally matured to audio's land of diminishing returns.

My nCores are doing uninterrupted duty in my studio but I've taken a step backwards to vacuum tubes in the main system. Even so, I'm convinced that switching amplifiers will convert even the most diehard linear solid state designs.
I'm having a hard time understanding the phenomenal increase in cost. Obviously more robust power supplies, upgraded switching modules, I/O sections, and even stupidly exotic casework, will increase costs. But is it really a 10k improvement?
Your observation on pricing may be a factor in these not getting more attention and buyers. The two primary manufacturers are getting $9K and $12K for what is essentially an improved and more powerful version of the Hypex Ncore amplification module and switch mode power supply module available to the DIY community for about $1,500 per pair. CNC milled aluminum cases are available from AluminatiSound for about $1K per pair. Assuming the modules and cases are both a bit more expensive than the DIY versions, the $9K version doesn't seem too far outside a typical audio equipment manufacturer's margin, but the higher priced version seems priced too high to me.

This doesn't take away from how good the amps sound but I suspect the dramatic increase in cost (above what the DIY community pays for NC400 parts), skepticism because of poor sounding earlier Class D efforts, and folks waiting for the next best thing in this relatively fast moving segment of the market, may contribute to less chatter and slower sales.
It is an odd phenomena that anything viewed as digital is considered obsolescent once a new version is announced. We're probably wired that way from watching digital computers evolve. But it creates a real financial and long-term satisfaction risk in buying very expensive "digital" amps.
I agree with your observation Electroslacker, which is likely a result of the logarithmic rate of advancement of the technology. The other issue with these amps that some may have a hard time overcoming psychologically, is that the sum of the parts cost is low unlike conventional A or AB amplifiers with their many capacitors, expensive transformers, large cases, etc.

Small size, low heat, great bass and absolute quiet have been consistent market drivers for the technology but, with the NC1200 amps, you can also have great sound through the entire frequency spectrum (IMO) so the experiment has been to price them based on SQ, and not the cost of parts and assembly. The absence of chatter here and on other forums implies not too many buyers yet, which may be either because of the cost, or the risk of obsolescence as you pointed out or .... maybe the owners are busy listening to music.

I did find a more recent thread on the topic over at "What's Best Forum."
ANother valid point by ESlacker!

Digital continues to evolve, unlike older analog technologies, which are fully mature these days, so ongoing change and improvement is still to be expected for teh foreseeable future.

So its like buying a computer. Invest under the assumption that things will likely still change for the better and that costs will also likely go down for what you get down the road as well.
Analog not evolving and fully matured? Considering the rapid advancement in switching amplifier design the gist of what your saying is understandable.

On the other hand the Bernie Grundman vinyl remaster of Weather Report's "Birdland" alone has rocked my analog world. A recording that highlighted every early digital production mistake possible has been substantially massaged back into realistic sound is a huge evolution.

Not long after the Grundman release a Benz S Class cartridge, USB microscope and Dr. Feickert's Adjust+ has made far greater sonic improvement on my old turntable than my entire switching amplifier evolution from the PS Audio to nCore. IMO this is a vinyl playback must do.

And I haven't even touched on the fabulous sound of the KT150 vacuum tube. Nah, the only thing fully matured about analog are the majority of us old fogy's who continue to make the effort and enjoy the glow.
In response to your question, IMO, the tech did not quite match the expectation and the "realistic portrayal of the music" is where they did not stand the test of time.  I really wanted the Ncores to be my "last amps" since I enjoyed everything about them, except ultimately the sound.
The short story is that I sold the Claytons (to a buyer who still enjoys them), sold the Ncores, purchased and sold a few other high quality amps, and eventually purchased another pair of Claytons which I had upgraded by the manufacturer and enjoy to this day. 
Something to be said about good Class does sound "right" over the long haul
I used to be a retailer, and have owned a tn of amps, preamps, etc

In class A I owned a Kinergetics KBA 75 and decades later a Parasound A23.

Tubes; Joule Electra OTLs, 4 Accoustat servo amps (modified), Moscode 600,

Class D has come a long way. I find the newer kit very listenable, while providing considerably more bang for the buck.
"I find the newer kit very listenable, while providing considerably more bang for the buck."
No argument with that statement, particularly about "bang for the buck," but that was always the strength of Class D.  There is a pair of Atsahs on sale here now from the dealer at $4K, which 2 years ago would have been a steal.  Putzeys' Mola Molas, Merrill's Veritas, and Reich's Theta Prometheus monos have all been selling at less than 50 cents on the dollar.  I have no longer been hearing raves about these NC1200 amps, although their NC500 siblings are said to offer nearly the same sound quality for a fraction of the cost.   I never had a problem with the Ncores sounding "good" but just couldn't make them sound "great."
That is an interesting and informative epilogue Mitch. We all want it to be true...low cost, low heat, high fidelity; and I suppose that it will happen, but I guess we're not quite there yet. Class A in solid state and tube forms seems to be about the best thing available, although it still is far from perfect. I think maybe the top Jeff Rowlands might be an exception from things I've read.
I think maybe the top Jeff Rowlands might be an exception from things I've read.
Guido thinks so, as do some others.  I haven't heard them but would like to understand what Rowland did to mitigate the sort of unnatural staging/decay/ambience that I (and others) hear from those modules.  The Bel Canto Black amps are also constructed using Ncore modules and are said to sound quite good.  

The two Class A amps that ended up on my short list were the Clayton M300s and Lamm's M1.2 Reference.  I owned both at the same time and could have lived with either, but the Claytons won out, mainly due to having more power (which my speakers need) but also for the quality of their bass and for their naturalness.
I have owned Jef Roland kit and he is a great designer, but does anybody really think he is smarter than all the other designers moding NCore/Hype, etc?
Ncore, like ICE has some interesting features. You can use your own front-end, and in that way you can use whatever kind of technology you want which can affect the sound quality. I believe for instance, JR was using a transformer coupled inputs. You could also use tubes, whatever.

So, is JR a better Class D designer than Hypex/B&O ? I don't know, but I do think he could whip up some good sounding buffers.


Not all that many others have done much with the stock NC1200 amplifier module.  David Reich at Theta used a LPS for his Prometheus monos and I believe Bel Canto designed buffers for the Black amps and also for amps they use with the much less expensive NC500 modules.  Merrill and Acoustic Imagery used the stock NC1200 amplifier and NC1200 PS modules and changed some wiring and binding posts that probably made almost no difference - how do I know, because I tried 4 different wiring harnesses in my Atsahs.  If I had to guess, the right buffer would probable move the ball further than about anything else.  However, even Bruno's Kalugas apparently play second (or third) fiddle to the Rowland 925s and the Bel Canto Blacks.  I would like to hear those two just so I would know if they actually "fixed" the issues I have with the stock modules.