Digital Amp's

Hi All,
I was wondering what everyone thinks of the newer Digital Amps that are becoming more common. I think these Amps are known as Class D amps. Belcanto is one company that seems to be pushing this line, but most seem to be coming from the giants like yamaha and panasonic.

What are the pros and cons of these AMP's over your everyday Class A/AB amp?
Any recommendations or condemnations for digital amps?

Thanks in Advance
It's often misconstrued that the 'D' stands for digital. It doesn't. It was merely the next letter in the alphabet.

Class 'D' topology is old news, having it's first iterations pre-transistor. It is a compromise design that sacrifices sound quality for improved efficiency.

I think what you are referring to is the class 'T' amps that do rely on a digital process to produce gain and apparently have no such sound quality/efficiency compromises. I have yet to hear one, but they are really creating a stir in the audio world.
With regard to technical advantages, digital amps excel at just about everything.

How they sound is a subjective thing that you need to judge for yourself. Some audiophiles say they are great, while others complain. (What would you expect!).

One aspect that is worth considering is that digital technology is inherently less costly, although some manufacturers won't admit this and continue to charge high end prices. You can get a very powerful amp (eg:600-1000 watts) for less than a conventional 100 watt amp. This may have very beneficial effect on your speakers, far outweighing any sonic inferiority of the amp. That's true for my Magneplanar speakers for sure.
Many of the modern digital or switching amplifiers are superior to mid-fi Class A/B amps in dynamics and bass control (depending on power). However, I have heard none of them that really deliver the high-frequency realism that a good bi-polar transistor class A amp can. I have modded several of these and they get better, but still dont challenge the best non-digital amps.

They can be a good value if you are looking on a budget.

Steve N.
Empirical Audio
I'd check out the PS Audiio HCA-2.
I owned an Acoustic Reality digital amp, with the B&O module.
The HCA-2 beat it up, everywhere.
I've only heard a couple of them, and not the very lattest versions. I've heard quite a few of the Spectron's in various systems and didn't care for them. Thats not to say that they don't work for others in other systems. I've only heard the TacT's briefly in less than ideal circumstances, but, in that context they may be amongst the top three or so amps I've heard. If I was in the postion to buy anything in their price range, I'd make it my business to give them a serious consideration. It's interesting that Audioengr finds the top end questionable, as this is exactly where I'm uncertain of their ultimate quality. Further listening is required.
I have tried the PS Audio HCA-2 and recently Channel Island D-100 Both excellent amps but like Audioengr give me a Class A SS amp.
Third Audioengr's comments. Also they are really fussy about getting clean power. I could not run my PS Audio through my Tripp-Lite surge protector - even with dedicated line. But for good sound on the cheap, not bad.
I own a modified Tact 2150.
Best amp i heard period.
I owned amps from Pass, Classé, GamuT, Conrad Johnson and heard a lot of amps (i work in the hifi... and don't sell Tact unfortunately), the stock 2150 is already great but once modified (diodes, BG, high quality regulators) no amp can touch him below 10K$.
If you want a polite sound get a class A amp. If your liking is more towards "real" get the ICE powered H2O Signature.
Audioengineer and the others,
I value high frequency extension, dynamics and realism.
Any examples of Class A SS amps that you're referring to that are better than the ICE power amps?
Faziod..."give me a Class A SS amp." To whom should I apply for this "gift", which I agree would be nice to have. Can I get 600 watts into 4 ohms?. In the real world, digital amps are usually the best solution.
I suppose we all have our preferences. I prefer D or T class amplifiers,especially when powered from batteries over Class A. Class A would be my second choice in design. There's a haze lifted from the music when you get away from the Class A stuff IMHO.The class A gear I've heard always sounded polite and maybe a little rolled off..nothing wrong with that if that's what you seek.
Audioengineer- have you heard the Boz216/2200 or the LyngdorfAudio TDA2200?

Anyone interested in digital amps should read the WRHI review of the TacT SDA2175. There's copy at:
Totally agree with Gmood1
T class amplifiers loves clean power, i put a Audiophile APS on my system and the improvement was also great.
You can't judge ICE amps one any one you've heard. I've owned two, and heard three. It's hard to believe they all share the same PWM module.

PWM amps are more system dependent than any solid state I've owned. They love big power supplies in all attending components, and they want shielded power cords.

I'm having my DAC and transport modded. Every subtle improvement matters, one would never hear with any solid state IMO.
Eldartford, In my world, in my system, a 100 watt Class A amps sound the best. In your world, digital 600 Watt amps float your boat thats fine. To each there own.
Faziod, There are people, including I, who have heard the H2O, and very fine
Class A amps, on the same system. None preferred the Class A. BTW, No H2O
has gone to anyone for a mod, other than the builder.
I wonder about zero feedback amps. Haven't heard any. has anyone? How would you characterize their sound vs. the new digital amps?
My Pass had zero feedback. These days, zero feedback is not an unusual thing. In fact, there are "digital" amps that employ zero feedback.
"I wonder about zero feedback amps. Haven't heard any. has anyone? How would you characterize their sound vs. the new digital amps?"

Woodburger- Muralman1 is correct,the Tact M/S 2150 have no negative feedback.

Muralman1- did you get a chance to check on those parts?
Muralman1, since I have seemed to ruffle some feathers I have only heard in my system the 2 class D amps I mention above in my post. Of those 2 class D amps I auditioned, my class A amps have a wider soundstage, better front to back imaging and deeper bass. As I also mention in my initial post the 2 class D amps are excellent amps but I happen to like my class A amps better.
Understood. No worry, we are all preened. :)
Muralman1. I do not doubt your statements here however, it would be appropriate here to qualify the speaker you were using to compare the two topologies and keep things in perpective.When you mentioned "None preferred the class A amp" over the ice amp..... Driving an Apogee Scintilla with any amplifier regardless of the amplifiers topology can be a compromise at best and certainly not an appropriate analogy here. Perhaps the very reason you elected to choose the H20 to begin with,no? Futhermore, what class A amps were you using for comparison? Most of us are aware that all amps are not created equal regardless of topology. While I have never heard the H2O, I have heard a few other ice amps and like Faziod....I wouldn't put them in the same leaugue as the better pure class A amps out there.
Ecclectique, If I were the only person singing the praise of the H2O, then the my outrageous speakers would be central to the H2O's relevance in use with normal systems. There are H2O amps powering a wide range of speakers now.

As much as I like class A amps, I love tubes more. To many, tubes beat class A when it comes to airiness, and depth. One only has to read 6Moons, and Audiofankj's reviews to see how H2O stacks up against tube amps. In both instances, the H2O has usurped their beloved valve gear.

As I mentioned, the H2O bares little resemblance to other ICE amps. It stands alone, with it's loaded analog power supply.
Muralman, if I'm not mistaken you seemed to have had the same enthusiam for the eAR amps not too long ago. Things change, new products surpass old ones (sometimes at least). Perhaps you might share your thoughts on the similarities and/or differences between these two digital amps?
Even better yet, Muralman, as you have owned a quality class A amp (not the best out there, but respectable none the less) why not in a nutshell explain where you thought your Class A amp excelled.

For example when you owned the Pass Labs X600 monoblocks what did they do well?

Then when you swapped to the eAR mono's - what was improved?

Then when you moved onto the H2o Sig Mono's - what was improved?

That is always more helpful to most people on here, rather than just hearing " this amp is much better and blows the competition away."

Thanks, for the added input Vince. :)

As an aside, when I began looking into the H2o Signature monos, I was suprised to speak with people whom had replaced amps the like of Pass Labs X600 monos, VTL 450 monoblocks, and others well into the $12,000-$16,000 new range. To have an amp in the mid $5K range compete in that arena, let alone better it to some was well worth looking into for me. After the piqued interest, I left the rest up to my own ears...
Hello Audiofankj.

I think I would have been careful to say the amp in my hands have blown the competition away in my system. Even though I never said that. :)

I don't think I stated on this thread, my speakers are the 1ohm Scintilla. On general discussions like this, I am leaning on the more normal systems of yourself, and of Strajan, the reviewer of 6Moons. Systems I figure readers can identify with more.

Frankly, I think it is a feather in Henry's (H2O) hat, that it performs so well on the most difficult speaker load devised.

I had moved from all tubes to tubes and solid state when I switched my Apogee Stage speakers to larger Apogee Duetta speakers. They are both nominal 4 ohms, but there's a lot more panel to drive. I tried the Pass X150, and liked the results. There was a nagging high frequency beam I never was able to rid of. At the time, it was my best system sound.

In anticipation of getting the Scintilla, I bought Pass Labs X600 monos. On the Duetta, it was more dynamic, and warmer than the X150. At least one listener liked the X150 better.

The Scintilla is not just another Apogee. It is a partial bipole. It's presentation is simply music in the room. Any amp that can push the 1 ohm Scintilla is wonderful, in my book. Never mind one Pass mono had heat stroke a number of times. The sound was bold, and dynamic. The bass was fugitive, however. The sound was the best I'd heard in my home.

A fellow Apogee owner mentioned that he had heard the little known Acoustic Reality eAR amp on his Scintillas, and it was great. I couldn't see why. The Pass's noise level, and distortion stats are way better than that of the eAR.

I gave it a try. He was right. The diminutive eAR gave up on some depth and wall of sound, but with the help of a big gulp preamp, it lifted a heavy veil I didn't know was there. It also gave the bass voice. It was the best I'd heard in my home.

Enter Henry Ho, builder of class A amps with enormous reserves. I asked Henry if he'd try the ICE module, in an amp of his device. He did, and loved it. Several months later I got my H2O Signatures.

The H2O has a power supply that would do a class A amp proud. Henry said, with the ICE module, "The highs are very hard to get right." Get it right he did. The whole of the spectrum sounds quite natural. With it's big analog power supply the H2O improves on the eAR. It gains in bass authority, depth, slam, naturalness, and weight.

I never have written a review of my amps. When I got them, they were the only Signatures around. I wasn't even sure if they were going into production. There are great reviews out there now. I'm willing to answer questions, or provide more details.

Thanks Vince. I didn't mean to sound like I was putting words in your mouth. I was familiar with your power amp progression, however I am not certain others are. I think most don't realize the people buzzing about the H2o's have tried a good many amps out there... not just moving from a Yamaha receiver to a power amp... and singing the praises of the "flavor of the month" - time will prove where the H2o's stand. I am quite sure we already have a pretty good idea too. :)

Hope all is well with you and your family out west...
Muralman1...You mention the eAR amp. I have toyed with the idea, but now find that a similar product is available from Red Dragon audio, right here in the good old USA. It uses the latest 1000 watt ICE module, in a simple neat package. What do you know/think about it?

Look at the H2O review at 6Moons. In it, Stajan compares the H2O Sig to the nicely packaged Jjaz. The 1000ASP has been popping up in, "High end" amps since it's introduction. They all share pretty much the same sound. Henry, of H2O has tried coaxing a good sound out of the 1000 ASP with no success. For great sound, there is just no substitute for a strong analog power supply. Like the review, points out, 1000ASP amps do sound good, just not on level with the H2O.

Muralman mentioned Henry trying to get good sound out of the 1000ASP, and Henry had told me the same. To expand a bit upon what Vince stated above, the key differences between the two ICE modules 500ASP (in H2o can be purchased without power supply) in which case Henry then designed his analog power supply to best integrate with the ICE module.

If memory serves me correct, the 1000ASP ICE module is ONLY shipped from B&O WITH their switching power supply, and from what I have heard and/or read of that ICE module in other amps in reviews it has not compared favorably. This is what Vince referred to from Srajan about the Jjaz amps that use the 1000ASP module. They just don't sound as good. Or at least not *yet* ...

FWIW - I had also listened to/auditioned the Rowland 201 and 501's and didn't find them to be in the same league as the H2o's... YMMV of course.
Thanks guys.
Say Dlite, read my comments in another thread "New H2O Signature S250".

These amps are the real deal. However, be prepared to break them in for a looong time. That's not so bad really as I found it rather fun to hear how the amp progressed every week or so.