Class D = Trash?

Was compared against Emotiva and it did not come close to the power and sound.

Emotiva is a brand I had really high hopes for.

Best,

E

Laugh if you want.  You can Spend $10,000 or you can spend a few thousand.  The Crown International Drive core 2 amps are cheap and have many turning in their esoteric amps. Lexicon uses Crown Drive Core technology.   Was compared against Emotiva and it did not come close to the power and sound.  These are going in home theaters. Google it yourself.  
I still run a Crown D150 Series II and it still sounds great.  Over 40 yrs old.   No, Not like a Levinson, but close to a MAC. which is good.  The Drive Core II are supposed to be better.

I guess what I'm saying is:

When I worked in circuit design we just threw a bunch of bypass caps of different types into the power supply without ever measuring their effectiveness or cost/benefits.

If I did this again, I'd take a more rigorous approach to every single power supply bypass cap. Spend money where needed as opposed to a shotgun approach.

Ahhhh, good times back then. :)

Best,


E

@atmasphere

Hah!

A recent phrase has made it into the news, I'd like to co-opt as a statement I never want to make:

I am being dominated by my loudspeakers

Speakers, like friends and family, should be easy to get along with for me. Not the secret Mistress whose every whim should be catered to. That's what secret mistresses are for.

About headphones and power supplies:  True, I also think it's a way of checking for checking the effectiveness of power supply filtering. For instance, if you get a lot more HF in your supply, may mean you need less inductive filter/shunt caps. It is also a way of knowing when you have done enough, so if I ever worked in the field again, it is a technique I'd try to apply to see if I could learn about any power supplies I worked on.

Best,


E

Personally I have lost all interest in hard to drive speakers because I find their total cost of ownership just too high for little value.

+1 on that!

When you can connect headphones to the power supply of any amplifier and hear the audio signal, you may count on the fact that the power supply is contributing to IMD. This is a very audible form of distortion! It is for this reason that we have a separate power supply for our driver circuits as opposed to our output circuits.

IMO this should be the case in a class D amp too, and I think that should pan out as the input circuitry usually has very different requirements as opposed to the output section.

Tim,

I wanted to add that though I have not have a chance to listen to one yet! But I believe the D-sonic amp is an great amp from what I have read.  And ice on the cake is the price especially.

Henry

Hi Tim, Thanks

I apologize for what I wrote was not very clear. So let me rephrase and make it a bit more clear. You’re right that there is not a direct relationship between good bass and an analog power supply, which makes sense, after all power supply is but one of the many fundamental aspects of any amplifier design. Great sounding power amplifiers requires many aspects of the design, and not just the power supply. What I can say from what I have implemented and heard is that an unregulated analog power supply seem to always sound better than those with SMPS. And this is strictly in the context of class D Icepower. As indicated, I have implemented and listened to the NCore 400 modules with an analog power supply of my own design, but cannot compare to any Ncore (400 or otherwise) modules implemented with SMPS and so therefore cannot make any evaluation as compare to the Ncore 400 modules with my own an analog power supply. I have requested to buy sample of Ncore 1200 from Hypex to test as I am a manufacturer and have been declined by Hypex. It seems as though Hypex wants to supply to only those manufacturers with reputable brand names, sort of exclusive club if you know what I mean, since H2O is a no body apparently, and that is my feeling. My goal is obviously to find the best technology which sounds good to high-end community. No matter though, from what I have implemented and heard, especially with Icepower, there is absolutely nothing to fear, at least from my point view.

Henry

Well... a lot of techy discussion here... and... I don't really know why my "Class D Audio" SDS-470C sounds so incredible (e.g. Ice vs Hypex vs something else or switching vs linear, etc.) - I just know it does.  

And... it seems to sound as good or better than my other amps, which are very good.  

And... I've not tried any other class d amps... so... I have no basis for comparison - I'm not really sure I need any - it sounds so grand!    

Todd, I could only find 12. I took them all at once. Nothing happened. My breath does smell like oregano, though.

Eric, 
" I am going to start another thread I think, for people who LIKE class D. :)"
Please do!

The valium is inside the amp. The pills look a lot like resistors.. just pull them off the circuit board. It'll be fine

@guidocorona ,

1) Once a class D is broken in is it stable from then on; or will it need to be broken in again if it sits idle for an extended period? (Actually any well-informed reader’s input on that would be much appreciated.
2) I just bought a used Audiosource on eBay for $60. When do I get my 500 Valium? Can I get more if break-in takes longer than 1,500 hours? Is this an honor system?

Hi Henry,

     Thank you for taking the time to respond in such detail to my question and stating that you do think there's a direct relationship between an analog power supply and good bass response in an amp. Given your praises of regulated amp output voltage, which the switching mode has but which the analog power supplies typically lack due to expense,  I would have thought the relationship between an analog power supply and good bass response would be less direct. However, I'm fairly certain it's best to defer to your knowledge and experience on this matter.

     It's very interesting and encouraging to know that you're continuing to explore the potential of the somewhat newer class D power modules such as the Hypex NCore 400 modules along with corresponding Hypex switching mode power supplies.  I would be very interested to know if you discover varying performance levels between these modules paired with the various Hypex smps (NCore 1200 and 600 smps) and the NCore 400 modules paired with your own analog power supply.

     Strictly from my subjective viewpoint,  the most obvious differences I've noticed between using class D and various class A/B amps(Adcom, McCormack and Aragon) in my system are improved bass response, a reduced noise floor,  increased dynamics (especially on content recorded in hi-res 24/96 format), increased detail and a more neutral sonic character in general.  
     These benefits were clearly noticed on the first 2 class D amps I owned (Class D Audio SDS-440-CS and Emerald Physics EP-100.2) and these qualities are even more clearly noticed on my current class D amps (D-Sonic M3-660-M).
      Just to be clear, I was not offended with anything you said and agree that there is no absolute in this hobby.

Thanks Henry,
 Tim   

Well, again, not a big deal, but this from a review on the Krell FBP:

The output stage in all FPB amplifiers employs a free-floating feedback arrangement wherein ultra-fast regulators independently monitor the output stage and respond to the smallest drop in current or voltage with regulator response that is all but instantaneous.

Bit of useless marketing/design trivia for Krell fans. :) Of course, this is only the output section, but it would be VERY weird to regulate the output but not the inputs, since the latter is much cheaper to do.

Best,

E

@h2oaudio - Since I'm not that big a Krell fanboy, it is VERY likely I got the models/series wrong. :)

I only wanted to point interested parties to examples.

I am going to start another thread I think, for people who LIKE class D. :)

Best,

E

Erik,

I believe Krell FPB does not have a fully regulated power supply from front to back.  The KRS series does and maybe the Krell master reference as well.  Though to my belief that power supply is one fundamental aspect of amplifier design, but it is only one of the many aspects which make the amp sounds good such as topology and devices being used, implementation to name a few. But I digress since we are talking about class D so let us switch (pun intended) back to class D channel shall we?

Todd, Thank you.  But I admit my knowledge is very limited actually compared to some of the GODS of amplifier designers such as Nelson Pass, John Curl and quite a few other designers.  I am a rookie compare to these amplifier designers.  I just know enough to make the amp sounds halfway decent by lots of experimentation.

I sincerely hope I did not offend anyone with some of the statements I made.  Please remember that my opinion is just that...one opinion.  It is just happen that I am a manufacturer.  And more importantly, what I referred to as "BETTER"  is only in the context within my system and others system which I heard, and furthermore to my ears and my ears only.  I do believe lots of members on this board have been around long enough to know, that there was not, is not and will never be one absolute.  It will always depend on the system as whole and more importantly listener's preferences, type of music, room acoustic and the list goes on.  And to answer the OP's questions.  The answer is NO.  Far from trash actually.  Then again, just like what I just mentioned above.  It depend to whom are we asking?  So the correct answer I believe is YES AND NO :-).

Henry

One interesting experiment I read about I've wanted to try is to actually LISTEN to the amplifier power supply lines. The + and - supplies are, in theory, at fixed DC voltages but as the music plays, the current draw will cause the supplies to sag with each note. You can actually attach headphones (carefully, wth appropriate circuits) and hear just how much effect driving speakers has on the power supply.

This technique can be further expanded to analyze the actual frequencies that the supply is worst at isolating, and to add appropriate filtering. A fussy technique I don't know if anyone but one vendor (probably out of business) has ever done. Still, fun idea.

In stereo amps, this effect is probably one of the main reasons for increased cross-talk between channels.

The points  @h2oaudio makes about regulated vs. unregulated are pretty much true. VERY few analog amps are regulated at all. Krell did this with the FPB I believe. Sanders's Magtech is what I would call semi-regulated. Brilliant compromise.

Doing linear for a carefully implemented input section also makes a great deal of sense if you want to get the best you possibly can out of it, without requiring a massive investment in hardware that a fully regulated amp would need.

Best,

E

Henry, thank you. While I understand only half of what you're talking about, the detail and knowledge in your post is superb.

Tim, Thank you.

I think a bit more valid conclusion as to which type of power supply is better is to have the same amp with SMPS and then the same amp with analog power supply given EVERYTHING else is equal. I emphasize everything is because as you would agree a front end and/or a preamp or even speaker wire can influence the sound, for better or worse. First, let me clarify that there are two fundamental differences between the two type of power supplies we are discussing here.  One being the SMPS and the other is the traditional analog power supply and that is obvious. But another big difference which is also worth mentioning is the SMPS type is being regulated...Meaning that the output voltage is held constant as long as current draw from the load (the amp) is within the supply's design capability.  And that is very desirable in audio power amplifier design or anything electronic for that matter.   However, regulated analog power supply for high power amplifier is very expensive to design just from the standpoint of hardware involve.  This is the very reason why regulated analog power supply is mostly done in preamplifier circuit since power involve is not huge, compared to Power amplifier.  In fact, 99.9% of power amplifier out on the market have been designed using an unregulated analog power supply, at least for the output stage. A fewer design may have a regulated analog power supply for the input and maybe a driver stage, but power supply for the output stage still is unregulated.  Stable voltage supply rail is highly desirable since changing voltage supply rail can change biasing current in conventional discrete transistor design especially.  Also, change or reduced in voltage supply will also limit how far the signal can swing, after all the amplified signal can only swing as far as the available supply voltage rail, and as  a result power is reduced.  Though the first effect (changing voltage under dynamic condition) is much more detrimental than the secondary effect of reduced power IMHO.  Due to those effects mentioned the result will turn for the worst in the final sound through the system. This is the fundamental reason (not the only reason of course) why most power amplifier can sound quite good at low volume but falls apart when pushing hard at high listening level, and especially into a difficult speaker load, because an unregulated power supply will sag (drop in voltage level) under heavy current demand from the load. While the analog power supply we are discussing here is not regulated, though it can be.  From my experience, an regulated analog power supply is always better than an unregulated analog power supply, again given everything else is equal. Then again, there used to be a debate( isn't it always with audio :-)) that an unregulated analog power supply can actually sound better than a regulated one.  Note that so far I have made a differentiation between a regulated and an unregulated ANALOG power supplies and not SMPS.  SMPS by design is always regulated.  Please note also that so far I have only mentioned power supply topology but in regard only to conventional discrete transistor design as in typical Class A and Class A/B design and not with PWM switching amplifier.  As mentioned above I preferred a regulated analog power supply for conventional discrete transistors design, simply because in class A/B and especially class A, always draw current constant current, and can be lots of it if it is class A or a heavily biased class AB. The reason is simply that if the supply is not regulated, the voltage rails will sag significantly resulted in lots of ripple on the DC rails.  And the end results will end up with is noise, hiss and hum.  And this is only under static condition (no input signal so no amplification), and will get worse under heavy dynamic condition where heavy current demand is asked for.  And that is very true for class A/B power amplifier.  But what we are talking about here is switching amplifier.  There is no constant current being drawn here as in the case with conventional amplifier. Well, there is but very tiny amount of current being drawn. The amp only draws current when there is signal.  But more importantly when it does draw current, but unlike conventional design, the transistor does not spending so much time in the linear region because the output stage acts like a very (make it extreme) fast switch.  And therefore, there is not much power dissipation as heat is being generated.  So this is the very reason why it runs so cool and efficient as we all know about class D amps.  So for Class D I really think the important thing is to be able to deliver huge amount of current but FAST and as fast as you can and not so much of being regulated or unregulated.  Though I got to admit that my intuition tells me from experience that a regulated analog power supply (mind you) even for the output stage would give a better result. I don't know since I have not tried it neither with SMPS nor regulated analog power supply, with class D that is. I have tried it with conventional design and for sure regulated supply wins hand down. There is something about switch mode power supply which I need to investigate further.

OMG, I can't believe I went this far and still have not answer Tim's question :-).... So without dwelling into too much of all of the technical jargon, the short answer is YES!!! at least what I have tried so far with class D.  I apologize for the post being too long, and in all honesty, this is the very reason why I decide not to anticipate with most of the discussions through the years as this took me hours to compose something like this as I am not a very good writer.  Though I found most of the discussion very interesting to say the least.

There is one confession which I need to make and that is coming from conventional strictly pure class A design through the years, I always chuckle and LMAO at time when I read debate where a piece of wire would make a difference in the final sound.  Well, I have stopped laughing ever since dealing with Class D.  Boy, talk about temper.  Just a simple bypass cap, which used to make tiny (if at all) difference in sound with conventional design, but with class D? It can sound heavenly or like trash.  The same goes for type of rectifier being used, and the wire and ....
 And for the record, the H2O has regulated analog power supply for the front end and unregulated power supply (and huge at that) for the output switching stage.  Also, I have finally manage to get a pair of the NCore 400 modules and have implemented them with a similar power supply which I have implemented for the H2O using Icepower module. I have been listening to the Ncore and have been rotate the Icepower in and out from time to time for comparison for the last month or so. Now what I need is to have is an NCore with switching mode power supply which design by hypex for real comparison.  Hopefully I would have a better insights on the difference in sound.

Henry

Thanks for your kind words, Todd.

It's hard to be level when so many forces on this site want you to be extreme. :)

Best,

E

Hi Henry,

     I respect your knowledge and experience as well as your H2O amps.

     I realize you utilize large analog power supplies in your Icepower based amps, rather than the more typical switching power supplies, and your amps are known for their excellent bass response.

     I own three class D amps that have all been used to drive my Magnepan 2.7QR speakers at separate times.  The first two were both stereo amps that have analog power supplies/toroidal transformers, a Class D Audio SDS-440CS and an Emerald Physics EP100.2.  My current class D amps are mono-blocks that have built-in switching power supplies in their Anaview/Abletec power modules, D-Sonic M3-600-M mono-blocks.   

     All three class D amps produce the best bass I've ever heard from my Magnepans but, IMO, the D-Sonic monos with the switching power supplies have significantly better bass response than my other class D amps with analog power supplies.

   My former class A/B  Aragon 4004 MKII amp also used an analog power supply that included 2 very large and heavy toroidal transformers. Both of my stereo class D amps, with much smaller toroidal transformers, and my class D monos, with small and lightweight switching power supplies, all have much better bass response than my former class A/B amp had even with its very large analog power supply.

    Of course I realize you don't want to give away any trade secrets, but I'm curious on your thoughts about whether there's a direct relationship between an analog power supply and good bass response in an amp.  My personal experience implies there is not a direct relationship but I sense the truth is likely more complex and think it is best heard from an amp designer such as yourself.

Thanks,
  Tim

"What I can say with confidence is that an analog power supply in class D does give you that full sound that class a/b amps posses."

phd,  I could'n agree more, but I would add AND THEN SOME...Or a lot more :-).

Disclosure: I am a manufacturer using Icepower modules with Analog Power Supply.

Henry

Erik, your reasonable manner is so refreshing after some of the epic thread battles of late.

Thanks for your input on ICEpower when I was in the market. I'm loving my ghentaudio monoblocks and was sceptical before I spoke with you.

Bass and amps is a funny, funny thing. Some speakers are hard to drive in the bass and sometimes that is malicious. A speaker that requires a particularly beefy amp is called "discerning" and sold at twice the price it would be otherwise. :) Some speakers are hard to drive in the treble. This is another area where some amps probably show significant audible differences. Personally I have lost all interest in hard to drive speakers because I find their total cost of ownership just too high for little value.

So while I think globally panning Class D amps as inferior to analog, there may be some truth to some amps performing better with some speakers, a problem shared by all amplifier classes.

Also, ICEPower among others, have optional input sections. This allows vendors to use their own secret sauce to the overall sound. From input transformers, tubes, whatever, so it’s quite possible for two vendors to use the same ICEPower or Hypex modules and get different results.



Best,

E

Have owned and sold hundreds of amps from entry to uber (I am an older audio+music-phile and one time business owner). Now retired, I enjoy refurbished and upgraded Aragon (A/AB), Goldmund (AB), bel canto (class D) and Virtue Audio Sensation (Class T) amps. With the right associated gear and setting, all are compelling performers. Cheers! 

Oh my, I hope it's not trash. I've got a Class-D amp heading my. Good to read of the positive experiences here. Would be nice to add my own happy story  in a few weeks. Fingers crossed.

Cheers,

Scott

Toddverrone, ah yes you could be right but somehow wyred4sound has managed to engineer the bass out of their amps. What I can say with confidence is that an analog power supply in class D does give you that full sound that class a/b amps posses.

One of the amps that I own, I made from Abletec mono modules, put 2 in a single chassis..... It took and initial 400 or so hours to break in and still continued to improve beyond 1000 hours.  I don't listen to this amp much, but none the less, it is no slouch.  Good bass, smooth midrange through the top end,  good detail... I like a few others better, but this is an amp does nothing objectionable and most could easily live with. 

@phd that's interesting you find class D weak in the bass without an analog power supply. I've found class D to absolutely kick booty in the bass department with the normal switching power supplies. 

Is there anything consistent in audio?!

I don't think there is a specified time for Class D to break-in. If there is and it would vary from one manufacturer to another should be mentioned in the manual. What we do know is that the longer they are powered up, the better they sound. The most important thing to keep in mind as they do require a lot of experimentation with different interconnects and power cables to sound their best and patience will prevail.

Look at Merrill Audio .they make Excellent amplifiers, and use Very good parts quality.I owned Mcintosh very dissapointmrnt wima caps donot belong in a $6k  amplifier I put Mundorf  supreme a Big improvement as well as resistors,wiring.
Class D  has nany variations, and   have their own implementations of class D.
Can compete with class A AB amplifier without exception. And a money back option I believe .I have them several times .I am going to purchase one myself.
I do recommend like myself a Very good custom Vacuum tube preamp 
Myself DHT  preamps are superior in Several ways 1 stage vs several in a conventional preamp.  The Russian 4P1L a fantastic most linear tube out there
As long as you have a veteran over 20 years in Vacuum tube design such 
as Radu Tarta, and the buyer chooses the quality of the parts choices. Far better 
Then most commercial average at best parts. 

I have a used D amp that needs to be re-broken in due to it being in storage for 1 year and 6 days. I would like updates at the following intervals - 600, 900, & 1500 hours...we can have listening sessions over Skype to monitor progress.

....I can see a novel business opportunity here...a 'burn-in service' for D amps.

Send me your new D amps and I'll burn them in for you.  When I think they're ready, I'll send them on to you.  First come, first served, and be patient.

Don't gasp...either you can put up with it, or I will. ;)  Pennies a day....

The best Class D I have heard does use an analog power supply (a large Toroidal trans with banks of power supply caps). In addition, if bass is of the utmost importance then an oversize analog power supply is a must. Don't get me wrong there are some very nice sounding Class D amps with a switching power supply but they seem to excel in the Mids and highs but lack bass to some degree or another.

Secondly...YES...break in time is crucial. When I bought my 501's, they'd been off for ~ year. I think they went through a break in period at that point, as they continually sounded better (and proceeded through the 'goofy midrange' 'echos in the mid bass' stages, then settled in). 

Very helpful post. IcePower is definitely improving with their revisions. 

All this talk about break in is interesting. And talk about breaking in a used amp is even more interesting. I wonder if the amp is "breaking in" the speakers? Not much science behind that thought, but there's not much science behind breaking in transistors either...  

I may be able to add a very slight addition, to the volumes written here. Leave them on, or at least let them warm up well-longer than you'd expect for a solid state piece of gear. LIke, a couple hours. Think of tubes x2.

I'm a Jeff Rowland 501-pair owner. They were early serial number 501's and I had a catastrophic power event over New Years (2017) which cause both to crater. (let's just say, imagine your heart rate and stomach acid level when you realize both your Rowland amps are door stops....) ANYWAY - after a call to Jeff himself, and lest I digress, he's a true gentleman and engineer with SUPERB CUSTOMER SUPPORT even with amps bought used. Anyway: I had two new amp modules coming my way. The old ones were ICEpower 1000ASP, revD. The new ones were ICEpower 1000ASP rev J. Indeed, Jeff uses an input stage consisting of a Furman transformer, but the rest of the amp is the ICEpower ASP module - and I don't know, nor anyone maybe, if it's "Plain Jane" or "Jeff's Secret Sauce". What I can say about the "new versus old" is the Rev J modules (circa 2016 ish ?? I don't really know) sound better than the Rev D boards (circa mid 2000's?), and that's even before the Rev J's are really broken in.
Secondly...YES...break in time is crucial. When I bought my 501's, they'd been off for ~ year. I think they went through a break in period at that point, as they continually sounded better (and proceeded through the 'goofy midrange' 'echos in the mid bass' stages, then settled in). I'm now in that painful process with my new modules "brand spankin' new" - still not there yet (as I can't just let them run, right now: in May I will be able to. Family stuff. I digress, again) however I can attest to the break in time....but I want to add, and I haven't seen it posted yet - leave those suckers ON, or at least get them warm for a few hours before critical listening. 

To the astute reading this, you may have caught the dichotomy of "catastrophic power event" and "need to leave them on all the time". Yep. The need to leave them on led them to their demise. I have since installed an isolation transformer and voltage monitoring circuit. I do see myself turning them off for longer periods of non-use. Also - I will be installing PC-1's as another line of protection, as well as (hopefully) some sonice benefits, but they sure sound good as-is.

Did you listen to the amps before purchase? 

you and your facts.

This link is to the best thread that I know of discussing the pros and cons of Class D technology vs Class A. The limitations of each technology is discussed in great detail.   
 
https://forum.audiogon.com/discussions/class-d-technology

I doubt class d will ever top a good 845. Don't fight it man, you know what's right!

madavid0,

  I just finished reading this entire thread. You've described your experiences using class D amps in your system as:

" Mid-range GONE.
Soundstage depth CRUSHED.
Euphonics DISAPPEARED.
Yes, resolution went up. Driver control went up, allowing me to play compressed rock/pop and orchestra with the speakers being able to render it all. But enjoyment in the sound is basically gone. Using my best power cable (LessLoss Original) improved performance, but didn't fundamentally change the amp's nature. I ran back to my headphones (Focal Utopias) to detox my ear canals."
" I can definitely detect that element of...whatever it is. Dryness? Poor blending of upper- mids into highs? Lack of weight? There's a SOMETHING to the sound that hints to listener fatigue.""Also....am I crazy or is this amp casting an unstable image? Like sounds don't want to focus and stay there."
Like....the vocalist says a word that happens a little to the right, but the trailing consonant finishes a little on the left.""Damn, 24 hours later and this amp sounds like trash -- rolled off / recessed mids again, soundstage depth almost gone...wow. I guess this thing with wired class D burn-in is true. "

     You seem to attribute all of the above to the class D amplifiers and you've received replies affirming these perceptions of the poor quality of class D from the herd of Audiogon usual suspects of class D naysayers that reliably chime in on most threads mentioning class D.
     Of course, the naysayers chiming in their aspersions was not surprising but, not being aware of you being similarly afflicted with their knee-jerk anti-class D bias, I was very surprised to read of your negative results.  I have no experience or knowledge of the Teac class D offerings but I do for the D-Sonic and several other companies' class D offerings. 
    As a user of 3 different class D amps over the past 3 years (The ClassDAudio SDS-440-CS and the Emerald Physics Ep-102 stereo amps as well as a pair of D-Sonic M3-600-M monoblock amps) in my system driving Magnepan 4 ohm speakers, I find it hard to believe the D-Sonic M3-800-S amp is performing so poorly in your system.  

   Even straight out of the box, I would expect the main attributes of the D-Sonic M-800-S amp to be immediately and obviously apparent; very good bass response and control, extremely low noise floor, very good dynamics with a smooth and neutral mid-range and treble that is also very detailed without any hint of brightness or harshness, In my experience with the D-Sonic monos, that use  Anaview/Abletech modules rather than the Pascals in your amp, there was a reasonable break-in period but I recall them sounding very good immediately and then proceeding to improve mainly in the mid-range and treble detail and smoothness over the first few weeks.  
     You not getting similar results in your system suggests to me that there may be another culprit or culprits responsible in your system.  There are several possibilities:  your left and right speakers may not have been properly matched at the manufacturer, you have 1 or more drivers blown/not performing to original spec or your D-Sonic amp is not functioning up to spec.

     There are a few methods to narrow down any issues that may exist:
1. Bring your D-Sonic amp to a friend's or dealer's and test it out with their speakers/system.
2.  Borrow a friend's or dealer's amp that you can verify is working properly and determine if the sound differs.
3. Take your speakers to a friend or dealer and connect them to their amp ,that they can verify is functioning properly, and determine if the sound differs.
  #1 will identify whether your D-Sonic amp is the culprit and #2 or #3 will identify whether your speakers are the culprit.
  I think trying #1 and then #2 sequentially would likely be the most efficient, least laborious and sufficient method to identify exactly what is causing your system's poor performance.
     If the amp continues to under-perform, I'd suggest contacting D-Sonic's owner, Dennis Deacon, about your issues.  He's very knowledgeable, reasonable and fair.
     If you go through this method, please post your results. If you're accepting wagers, please put me down for $5K straight-up on your speakers being the culprit.

     A final friendly tip: If you try your D-Sonic in a friend's system, don't expect it back without a struggle. 

Thanks and good luck,
       Tim 

Classe is definitely not trash. 

+1 grannyring

I have rocks in my head as my SS amp and server are always on. I also keep my air conditioning, heater, computer, night lights, and several other " dangerous" items on at all times. Good thing my neighbor is a fire fighter. 

northernfox: we've been super impressed with the Bel Canto REF600M as well. They're a huge step up from the old REF500M in my opinion. We're currently driving them in one of our demo systems being fed by the Bel Canto DAC3.7. An excellent combination.

@sanvara - I had a crown xls1500 that sounded great. Recently bought a used pair of Ghent audio monoblocks and they sound even better.. they're using the ICEpower ASP modules, I believe. I was doubtful they'd sound better.. but they do.