[ethirolle]

I am fascinated by the rise of "audiophile" Class D amps, and the increasing respect they get from reviewers and listeners. If you have been "converted" to Class D, I would be curious to hear what amp converted you, and what your journey was before you arrived at Class D. Did you come from Class A/B solid state, or pure Class A, or even tubes? What convinced you that Class D was right for you?

I am most interested in stories where Class D just sounded so good that you no longer felt you were compromising by listening only or primarily to a Class D amp.

My story first: I have been a Class A/B solid state amp listener for most of my life, starting with high-current HK integrated amp from the 1980s, and later with an Anthem receiver (which I still think sounds fantastic), and most recently a beautiful Luxman L507-u integrated amp. I even dabbled in tube amps with a nice mid-priced SET amp (Tokyo Sound Valve 100/SE). But on a lark, I bought a used pair of Bel Canto Ref500M monoblocks, and later a Bel canto Pre3... and these have become the core of my primary listening system. I just find them to be as good as anything I have ever lived with: refined & balanced, powerful and liquid-sounding. What more can I ask for? The sense of sonic realism is startling when I first turn on a good recording.

Cheap Class D can sound lifeless and grey. But well-executed Class D can hang with the big boys! (Though I will admit that I have not spent much time with some of the BIG boys, like Pass Labs pure Class A solid state amps...)

Thanks in advance for your stories of how you arrived at Class D!

Regards,
Eric

[stylerb]

do the Bel Canto still use ICEpower modules? i dont know much about class D but would like to know the difference between ICEpower, NCORE and Eigentakt.

[mresseguie]

Hi, Eric. Welcome to AC.

I've got both 300b tube dual mono amps and Class D amps in my 'corral'. The Class D amp is a Nuprime Evolution STA that I purchased a couple years ago. I typically use it in my main system during the hottest months.

I own a couple other Class D amps that I use in desktop (Nuprime's Omnia A300) or bedroom (IceEdge1200as2) applications. The IceEdge amps sound pretty good and are very powerful, but they lack the warmth of my Nuprime Evo STA amp.

Michael

[Phil A]

I've owned a few class D amps (and currently use one in the main system and another in a back-up system).  Prior to that, I've owned class A/AB amps (all the way to one which is still a current model and lists for $11k) for about 40 years.  I never envisioned getting a class D amp when I first heard them about a decade back.  While they had some nice qualities back then, it just didn't impress me as something I'd consider.  I first tried a stereo IcePower (probably around a half dozen years back) amp which I figured I'd end up using in a secondary system (where I had a class A/AB amp from a well known manufacturer) and I was shocked how much better the class D was (I used to think the secondary system shortcomings were the speakers).  I was even more shocked when it bested my $11k list amplifier (and that's not just my opinion as others heard it).  I think class D will get better when they start using discrete input stages vs. inexpensive op amps as the what the signal passes through first.  I think a lot of people just automatically dismiss them based on their pricing and based on some of the early models. 

[Early B.]

Well-executed amps of all varieties are expensive. Good Class D amps are now on the same level as good Class A or A/B amps. If I were gonna buy a solid-state amp today, I'd seriously consider a Class D amp due to convenience (lower weight, etc.) and my budget would be several grand. Tubes are a different breed altogether and there's no comparison  -- either love 'em or leave 'em.

[Zuman]

There's Class D and there's Class D...
Most Class D amps are analog, but I had a NAD Masters Series M32 digital Class D integrated for many years. I thought it was great, until I switched in a Modwright KWH 225i amp, which is Class A/B with a tube front-end and a solid state output stage, operating in Class A for the first 25 watts.
It was the single-biggest sound quality improvement I've ever made to my system, providing a much greater sense of control and heft and a smoother, purer-sounding top end. I don't know whether it is because of the triodes, the extra 40 wpc, the analog signal path, or the A/B operating class.
That said, I'm also intrigued by some of the newest Class D designs, and I believe that there are still breakthroughs being made which will benefit all of us. Progress continues even in Class A with companies like WestminsterLab, whose compact 35-lb Class A monoblock is being embraced by many ultra-high end enthusiasts who normally stick with 100-lb + monsters.
These are exciting times, and I think that the key mindset is to be open to the future, not mired in the past.

[cheesey]

Used all sorts of amps over the years. Tried a Spectron Musician 3 and never looked back. Bruno Putzeys changed the game- his ncore and now Purifi have removed the amp from the intellectual debate. Been using a Hypex nc1200 for a few years now and have the new Purifi 9040 on order along with a ncx500 stereo amp. Will use the nc1200 and ncx500 on 4 subs and the new Purifi on a pair of Acoustat 6600's.

[ethirolle]

Thanks all for your comments so far!

do the Bel Canto still use ICEpower modules? i dont know much about class D but would like to know the difference between ICEpower, NCORE and Eigentakt.

@stylerb: the Bel Canto Ref500M use ICEpower modules, but I think Bel Canto switched to using Hypex Ncore with the Ref600M, and I believe (tho I could not confirm) that this has continued with their latest models (Ref601M & Ref501S).

I have not had the opportunity to hear these more recent models, but the reviews continue to be excellent, so I think I'd love someday to audition them and perhaps move up the chain.

Speaking of reviews... Herb Reichert's review of the Ref600M from a few years ago (https://www.stereophile.com/content/bel-canto-eone-ref600m-power-amplifier-herb-recihert-september-2017) correlates well to my experience with my Ref500M: startling sonic realism and a beautiful sense of space. Those two things go a long way for me.

These are exciting times, and I think that the key mindset is to be open to the future, not mired in the past.

I could not agree more 
If I can get my sonic yayas from these slivers of technology that weigh only 10-20 pounds, and use 80-90% less power while not heating up my room, then I salute all the engineers who have made this possible! I have both traditionalist and technologist in me: it makes me excited to see progress and innovation in amplifier design, but only if it serves the goal of dishing up beautiful music

[newzooreview]

There are a few very well-done tests on Youtube. Alpha Audio uses a good format, combining bench measurements with very high-quality microphones and a panel of experienced listeners each with a different background. They typically record the full 2-hour listening session, and it's easy to discern differences in tonal balance, timbre, and detail with a pair of headphones. What they comment on is almost always apparent in the differences that can be heard in the recording.

One informative comparison was of ICEpower, Purifi, and the most recent Hypex (Nilai) Class D amps along with a Pass Labs XA250 (their reference). The contrast between Purifi and the Nilai is very interesting. The Purifi is detailed and punchy and the Nilai clearly portrays the harmonics in acoustic instruments and the timbre much more naturally. It's worth a watch: https://www.youtube.com/watch?v=NdZFAWe1Nxo

They also compare the Hypex Nilai (which they built from the DIY kit) to a Yamaha A S2200: https://www.youtube.com/watch?v=dkUgStoRzvs

And in their test of monitor speakers, they switch between the Pass Labs and Nilai with, again, audible differences. https://www.youtube.com/watch?v=U7sXOFirQKo

With their stereo Schoeps microphone setup, the recording easily allows for comparison even if it cannot capture the soundstaging perfectly.

Based on the GaN, ICEpower, and Tripath amps I've owned, along with the Alpha Audio comparisons and comments on this site, good Class D is on par with good Class A and A/B in many price ranges. In the cheap and cheerful price range it's generally better than Class A/B; in the mid to upper price range (say $500 to $5000) it's competitive and the choice depends on speakers and preferences, and above $5000 there are probably more excellent non-Class D options than Class D options. A generalization, obviously.

However, ICEpower is not very good, and some cheaper Class D has load-dependent frequency response (like the cheap little WiiM Amp I've owned or the measurements of the Fosi amps).

Good Class D, even the off-the-shelf Purifi and Hypex modules and power supplies, has a flat frequency response regardless of speaker impedance.