Atma-Sphere Class D… Amazing

Today I picked up my Atma-Sphere Class D Amps. These aren’t broken in yet. And they are simply amazing. I’ve listen to a lot of High End Class D. Some that cost many times what Atma-Sphere Class D costs. I wasn’t a fan of any of them. But these amps are amazing. I really expected to hate them. So my expectations were low. The Details are of what I’ve never heard from any other amps. They are extremely neutral. To say the realism is is extremely good is a gross understatement. They are so transparent it’s scary. These amps just grab you and suck you into the music. After I live with them some and get them broken in. And do some comparisons to some other high end Amps Solid State, Tubes and Class D’s, also in other systems I’ll do a more comprehensive review. But for now, these are simply amazing amps.. Congrats to Ralph and his team. You guys nailed on these.




Thanks! I’m looking forward to hearing more. What speakers? And what digital/analog sources?


You bought a pair of amps expecting to hate them? Strange approach to putting together a great sounding system. Could you elaborate? Your system, strategy, venue.

I have  Atma-Sphere MA-1’s with all the options. Have an Atma-Sphere MP-3 Vcaps and Caddocks. Both are 3.3 versions so current. Am running Bel Canto Dac and Streamer Dac back to back. Current versions. Running Roon with dedicated server.  Classe CDP-202, with Khorns with VCAP ODAM’s in the crossover. Running Cullen Cables for Power, Interconnects, and Speaker cables. Also have a set Gregiteks, Harbeth 40.2 and Magnepan 1.7i for some comparisons. 

I took Ralph’s word that I would like these amps. I have not heard any Class D I actually liked. Or would compare to a Fully Optioned Atma-Sphere MA-1. And now I have…. I am like I said very surprised. So far in some respects my MA-1’s do things better. And some respects the Class D do some things better. Once broke in I can’t wait to put them against some nice SS Amps. And compare them more to my MA-1’s. It’ll be interesting if I like them better in the end. But this is all subjective opinions… My own…. But my system isn’t a slouch system. And I run all High Rez files.

Hope that Answers your questions…. 

I should add I heard the prototypes a few years back at Ralph’s Shop. So I knew at that point they were really good then. But hard to compare till you put it in your own system. The system you are most familiar with. Tonight I got to do that. And is when I how special they really are…. Going to be a great weekend…

Pstores, I am waiting on my amps to ship. Then I will see how they compare to the M-60's , which I love. Also using the MP3 and a Shindo preamp I alternate, cause I love them both. Thanks for the write-up!

Does anybody really think Ralph would’ve potentially undermined his own core business and introduced a Class D amp if he really didn’t believe in the technology and its potential? I consider this to be one of the very, very few components I’d be willing to buy blind and expect to be nothing but thrilled, and I so respect Ralph for embracing new and promising technology due to his objective assessments of its capabilities rather than relying solely on his past considerable success. Most impressive on so many levels and falls solidly in my “holy crap I never saw that coming” category.

I have Atma-Sphere Class D and suspect it outperforms every other brand in its price category.

I can’t recall if Ralph mentioned anything about break in time, but he did say they have virtually no warm-up time to achieve best performance. I never noticed anything to contradict Ralph’s statement. Idle current is so low that it invites leaving them on 24/7 yet if the amps happen to be cold, they need little to no warm-up to sing.

A friend of mine is interested in an A-S class D integrated. He mentioned having read that Ralph’s Class D "sound like a tube amp" in only the best way. I have heard various models of Ralph’s OTL and a lot of great brands of tube amps.

I agree with Ralph and others who say his Class D sounds like the M-60 OTL above the bass range, which by any metric is a long-time tube amp gem (having won more awards than maybe any other current production amp.) It seems important to add this caveat: the ideal OTL load is between about 12 and 16-ohm with benign phase angle, which is rare, plus higher than average sensitivity. Class D has no such current limitations and can drive loads below 4-ohm which is verboten for OTL and a ratio of transformer-coupled tube amps.

OTL have a unique signature in the bass range, not necessarily worse or better than SS, just different, hence the qualification "above the bass." In the range of bass instrument fundamental tones, Ralph’s Class D sounds like a good typical class D amp: quick, neutral, superb and powerful. Of course, bass harmonics extend well into the midrange and treble where the Class D is very transparent in this category.

AFAIK for all Ralph’s prior amps, Ralph included a U-shaped copper shorting pin. Using the RCA input required users to short XLR pins 1 and 3 (1 is neutral/shield, 2 is positive signal, 3 is inverted signal; 3 shorts to ground to shunt the entire inverted section of the balanced input to minimize potential noise.) The RCA input of current production A-S Class D requires NO XLR shorting pin, hence none is included. Ralph said shorting XLR pins 1 and 3 has no effect on noise while using the RCA input.

Class D is clean. Seems like they just added some distortion and charge $5.4K for it. DIY NC400 Monoblocks will outperform these as a fraction of the cost.

Spkrplus, I believe they outperform the M-60. I’ve had s-30, M-60 and my MA-1.  I am not sure I’d say they are Tube like. But they aren’t harsh and bright like many SS Amps.  

Elangley01, No the just didn’t add some distortion and create some amps. This is a complete departure as to the way all other Class D Amps have been designed in the past.  Hence how Atma-Sphere got a new Patent in the Circuit Design. I doubt the NC400 would be close to having the sonic character as these do. I’ve listened to many high end Class D. Some costing more. And these are better defiantly better. On Monday I’ll have another more expensive Class D to run side by side in my system. Just to see how much bettter the Atma-Sphere really is. 


As far as “Break-in” Ralph said not a lot just a day or two. They share same components like Power Supply, Capacitors and such. Which pretty mush all need some “Break in” time. I’ve always trusted Ralph and his staff to give Honest and Straight answers. I hadn’t heard the finished product. But I know Ralph very proud of this product. As he should be. And he is the Designer. So I thought there maybe some Bias. But I think he down played these to me. These are truely an awesome amplifier.  Are they as good as my MA-1’s? In some ways yes. And others ways no. Will I like them better than my MA-1. Probably not. But the MA-1’s are Basically 4 times the cost,also. And they are simply a special amplifier. IMHO…  I’ll reserve comments on that for down the road while I get to compare them more. Need to get used to the Class D some. But there is no heat from the Class D. My house is super insulated. So the MA-1 do heat the room some after awhile. The tubes don’t run super hot because they aren’t driven hard. And they last forever it seems. But they do warm the room up. Hence why I got these. 

Sorry for the Typos and such. Doing this on my phone. Wished they let you edit your posts on here still. When I go to Edit to fix the Typos it won’t let me. Just flicks and goes back to normal. 


Nice write up OP and I completely understand your upfront nagging concern of what they will sound like. It comes from your past experiences and that is completely reasonable. I am most interested in these amplifiers and will also have to allow my trust in Ralph to win over some of my up front Class D assumptions.  Ralph is truly one of the very best designers and gentleman in the business.

The irony !    One of the best mfg of OTL tube gear makes one of the most highly acclaimed Class D amps yet.    Go figure

MA-1s/140wpc for $9,800, and Class D/100wpc for $5,400, into Khorns which need only a few watts? Time to be rescued by a less expensive 300B tube amp which sounds very much "like a tube amp"...

I would be open minded enough to try Ralph's Class D amps.   They would never release an amp that didn't sound great in my opinion.    Why bother?     $5400 is not out of line for.a great pair of amps .  Sure it's a lot of money, but you will spend that much for a really good 300b or more , unless you build it.  

The differences are baked in. Ralph designed them from the ground (literally) up.

I haven't heard the Atma MA1's but do have 97db speakers and the Atma M-60's are better than my 300b amp in my system. I used the Allnic 300b amp for years before getting the Atma-sphere. The 300b is great, but not as good in my system.

I also have had Bel Canto Ref 1000, and Merril Audio Veritas in my system, Although the Bel Canto was with Joseph Audio speakers. I am not a huge class D fan, although if you change your system to them, you can make it work well.

What convinced me to try them was Ralph saying he uses them in his system. That caught my attention. Then when discussing with Duke Lejeune, he said he was planning on getting them for his system, although he said the bass would be different from the M-60's, not necessarily better, and making the statement that the M-60's were a hard act to follow. That did it.

And do some comparisons to some other high end Amps Solid State, Tubes and Class D’s, also in other systems I’ll do a more comprehensive review.


I can’t wait for your precise and articulate tribute.

In full knowledge that you may only change one variable between comparisons, all other things being held constant.  This will invariably involve comparing components that are not technically equivalent.

But you know that, having read all of knowledge provided on Ralph's website.

No, not really.  I seek informed analysis from one who is cool, calm and collected and in control of their cognitive facilitates.

Idle current is so low that it invites leaving them on 24/7 yet if the amps happen to be cold, they need little to no warm-up to sing.

@pstores, congratulations on your purchase!

I've had my pair for ~ 2.5 months now, and leave them on 24/7; it is amazing how cool they run (like barely warm at all, unlike my other amp which is a Class A Pass). I might have 300 hrs of play time on them at most and think they likely have improved some over that time.

I'm feeding them with a Meitner MA3 and Sim 740P, and they are most certainly not out of place. 

Atma's are good but overpriced....400 watt Peachtree is 90% there and costs under $3,000....I'm hearing details I never heard with my tube and class AB amps that I love. Every piece of music I play sounds "new" with all this added detail...very exciting....but I still love my 845 SET Tubes.

Atma’s are good but overpriced....400 watt Peachtree is 90% there and costs under $3,000

So, you have completed a full costing analysis on all of the necessary inputs (defined very wide) in order to make this comparison?

Others may suggest the exact opposite of what you suggest - that Peachtree is utter junk and something that a person with more dollars than sense would consider buying.

Because 90% there is sufficient?

I say no.

Declare your interests. I have none.

What I do know is that I’d rather pay way more than 5,400 for a 100% "there" than 3,000 for something not quite "there" and possibly has unresolved component or design issues.

Why on earth would anyone settle for less at these price points?  I buy for keeps, not to experiment.

I’ll be comparing these amps to Pass XA series including the .8’s. As well as other amps. Will keep all other components the same. And will hold the Db’a the same as well. it’s going to be fun couple months doing some serious comparisons. 

    I still have a hard time believing they are this good. The realism is absolutely incredible.  

Ddafoe, yes you are correct they run very cool. I wasn’t that surprised by that. As Class D do run cool. Hence the reason I got them. It was a choice of Pass XA 30.8 or the XA 60.8, or Atma-Sphere Class D for summer listening. The Prototypes I had heard a few years back were pretty good. No way close to as good as these. So the apprehension was there.  I looked for reviews from owners and such. Then thought Ralph’s been a very straight honest person. And I feel he down plays his own gear some. So I took the chance. Besides $5400 for a great amps these days is cheap as hell considering what others cost. I suspect what I am going to find is these amps outperform many other amps costing much much more. Regardless Class D, SS or Tube. I am not looking for a certain type. I am looking for excellence . So if the Pass outperforms the Atma-Sphere Class D, or any other can within in my price range I am willing to spend…… That’s what I’ll end up with. I have a budget of $15,000 with selling my other amps and such. So at the end of the day. The best amp under $15,000 wins. As long as it’s not a room heater. With having a super insulated house that’s a concern. My MA-1’s I’ll keep for winter listening. As they aren’t going anywhere.


Yes, crazy isn’t it…

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The irony !    One of the best mfg of OTL tube gear makes one of the most highly acclaimed Class D amps yet.    Go figure

Thanks Grannyring and Sandstone….  Big jump going from Tubes to Class D. 


100 watts @ 8ohms per block, utilitarian plain enclosure. Does not seem that impressive.

The irony !    One of the best mfg of OTL tube gear makes one of the most highly acclaimed Class D amps yet.    Go figure

What's the irony?  Do you even know the meaning of the word irony?

That you say Go figure - you are blessed.


100 watts @ 8ohms per block, utilitarian plain enclosure. Does not seem that impressive.

@avanti1960 Really?  That’s how you pre-judge this amp from one of the most reputable designers in the biz?  Pretty shallow dude.  Have a listen and then see what you think.  I believe after that you’ll be searching for recipes on how to cook crow.  Bon appetite.



I got the Silver Faceplate. They look pretty nice in person. Looks doesn’t add much to the sonic qualities. Maybe give you some placebo effect. Like the McIntosh MC452. Looks nice. But not the best sonic qualities for an amp that expensive. I had one for a very short time before I sold it. I’d rather pay for function.  I guess the same could be said for Pass Labs Amps also. But hell I love the Pass Labs Amps. The First Watts are also damn nice amps. Glad people like Nelson and Ralph build for sonic qualities,  not beauty contests. That could make it that much harder for the common folk, like me,  to get some awesome gear. 




So, who is going to be the first to pop the hood and show us the engine.....with close ups?  Show us the meat!  he he.  

I don't like the way the logo looks.  It completely and utterly makes the amp a non-starter with me.  If a manufacturer can't design a cool looking logo then what are the chances of them making a great sounding amp?  I swipe left on this one.

Onhwy61, have you ever heard any equipment made by Atma-Sphere? Are you aware his Preamps are considered one of the best of the best? His Amps are legendary? How many listening sessions have you had with Atma-Sphere gear? 

  What I see in this thread for some reason is small number  of Atma-Sphere haters. To me that makes no sense. Especially the way Atma-sphere shares information and in a non bias way. And I’ll bet that none have spent anytime with the gear. Whether it’s OTL or his new Class D. The professional reviews say all great things of his amps. I’ve never seen a mediocre review let alone a bad review. And he doesn’t Advertise or really Market his products. Why? Because they are that good and he doesn’t need to. One of the few. I’d you have a grudge against Ralph whatever…. But not sure how you can bash a product you’ve never heard. That’s actually weird…. 


I’m pretty sure they found that logo to sound the best after testing many others.  Everything matters. 

 For the first time since the seventies I just moved from all separates to an integrated and now these show up. 
Does anyone know of a dealer in the Midwest?

@ddafoe Which Pass amp do you have and how does it compare to the GaN amp?

I owned the X250.8 for maybe 5 years and switched to the XA30.8 a couple years ago.

I find Pass to be very smooth, a tad warm, offers zero fatigue, very natural tone, and throws a killer front to back soundstage.  So far I find the Atmasphere GaN monos to have a very similar sound to my XA30.8.

"very smooth, a tad warm, offers zero fatigue and very natural tone", check.

"throws a killer front to back soundstage, ...", is slightly different but just as engaging I think so far at least.
I find the monos offer a maybe slightly less 'meat-on-the bones', but a wider soundstage, good depth but maybe not quite as deep, but offer a blacker background and ultimately allow me to hear in and around the instruments just as much, just in a slightly different way.

When I get more time I plan to swap back to my Pass and compare the higher frequencies.   That is one area where I haven't made a decision yet on how they compare.   I find the Pass amps to offer very nice high frequency detail and refinement, without being bright or forward.   

I can see why tube amp owners or Pass owners would like these.   Personally, judging them based solely on their looks, power rating, or because they are GaN based as some folks have done doesn't really hit the mark in my view.   They definitely sound different and very Pass like compared to most amps I've owned.  Some folks may love them and some not so much, but in my opinion they are not the type of amp you just throw in as just another Class D or GaN offering.   They are definitely worth a listen if the sound characteristics I mentioned above float your boat... 


 I’d bet that logo was picked,  and identified, to show .001 lower distortion and zero feedback on their OTL Amps. I’d bet since it was such a success with the OTL’s  they continued them onto the the Class D for same reasons…. But if you look closely at the logo…. It’s pretty damn cool design. And it’s been around for along time, decades. First I’ve heard of the logo complaint. 

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I’m pretty sure they found that logo to sound the best after testing many others.  Everything matters.

dDAFoe,  thanks for the comparisons. Specifically to the 30.8. I’ll be comparing them to the 30.8, 60.8 and a couple from the .5 series. So it will be interesting. I do love Pass Amps. And without doing a side by side I’d say your spot on. But can’t wait to do a side by side for the true comparison. Thanks again

Ralph has been making amazing amplifiers for a very long time. My next amplifier will be his class D monos. An acquaintance in Kansas has them and they sound great, will be visiting this client next week and look forward to another listening session at he home.

@pstores what preamp are you using?

Jerryg123, I am running an Atma-Sphere MP-3 with Vcaps and Caddocks. Tubes are Amperex Bugle Boys. 


@pstores you've evaluated these amps exactly the same way they were just described to me by an AS dealer.  "They sound just like the S-60's above the bass"  I'm currently using the MP-3 + S-30 in one of my systems and Pass in another, so you've pretty much nailed it for me now.  Thanks for the review.  Looking forward to cooling things off 😎