1. Home
  2. amps-preamps
  3. 197619-139155

Expanding the Class D Conversation: How Would You Characterize Their Differences?

Expanding the Class D Conversation: How Would You Characterize Their Differences?

I'm currently trialing the NAD M23 (1st gen. Eigentakt-based), and I find it intriguing enough to want to understand it better — which means understanding the broader sonic landscape of class D. So I'm crowd-sourcing.

In a recent exchange, the estimable Ralph Karsten (Atma-Sphere Music Systems) made two comments that stopped me cold. For those who missed it, here's what he said:

"IME, class D amps vary in sound more than tube amps, which is to say, quite a lot."

"IMO there is a bigger difference between various class D amps than you hear between various tube amps. IOW just because you heard one class D amp says nothing about how the next one might sound."

Link: https://forum.audiogon.com/posts/2885828

As I think through this more carefully, these are genuinely important claims. My own experience with tube amps confirms that they produce audibly distinct characters across topologies and designs. If Ralph is right and class D exceeds that range, then generalizing from one class D experience to another is even more hazardous than I assumed.

One specific question for Audiogon members:

If you have a Class D amp or have compared class D amplifiers, how would you describe their character(s)?

Here are some criteria I use:

  1. Frequency balance — Is the tonal response even across bass, mids, and treble, or does it favor certain regions?
  2. High-frequency texture — Are the highs extended and smooth, or edgy, grainy, and fatiguing?
  3. Bass definition — Is the low end tight and articulate, or loose and bloated?
  4. Midrange character — Does the midrange feel present and natural, or recessed and thin?
  5. Transient speed — Does the amp respond quickly to dynamic attacks, or does it sound sluggish and rounded?
  6. Dynamic range — Does it scale convincingly from quiet passages to loud ones, or compress the difference?
  7. Soundstage width and depth — Does it create a convincing three-dimensional image, or sound flat and narrow?
  8. Image specificity — Are instruments and voices placed precisely, or do they blur and wander?
  9. Background noise floor — Is the silence between notes actually silent, or is there grain, haze, or hash?
  10. Long-term listenability — After an extended session, do you want to keep listening, or has something been quietly fatiguing you?

If you can include relevant system context — room, speakers, preamp — please do. Those variables will help me interpret what the amp itself is contributing.

I'm less interested in rankings than in understanding what Ralph mentioned, namely the [vast] range of sonic signatures class D is capable of. Eigentakt, Hypex, Pascal, Purifi, GaN-based, etc. — all fair game.

Price is no constraint here — I'm interested in the full range of what's out there.

hilde45
hilde45's avatar
hilde45 OP
5,997 posts
 

@atmasphere Thank you for your generous and informative replies. And your corrections!

I suppose the factory burning down helped explain a temporary shortage, but my sense is that even though it was rebuilt (the article I cited discusses an upsurge of interest in the Chinese market for tubes) there is still an overall trajectory where tubes stick around but become more and more of a niche in the market.

decooney
2,564 posts
 

That "tube factory" information is way out of date about Shuguang, plant burn. A lot has happened since then too past 2-3 years. PSVANE picked up all the tooling and tube line from TJ Full Music for smaller tubes. Shuguang partner lines of tubes they've come out with since, and some of the overseas distributors have picked up these lines too. I have no affiliation with these guys, just sharing, showing. 

Shuguang-PSVANE right here: https://shuguangpsvane.com/collections/shuguang-audio-tubes

Again what I was floored about is just how many different rooms with tube amps, tube preamps, and so many other "tube" related devices after we've been led to believe its all slowing down, clearly not the case looking over all of the Axpona walk-thru videos too. 

The good news is, the audio industry seems to be alive and well after quite a few years of slow-down post pandemic. Quite a turn out this year at Axpona, new dealers, new distributors or old ones, new options - many showed up. Very cool!

 

decooney
2,564 posts
 

@atmasphere That really depends on who you talk to. I can point you to some people who say quite the opposite. FWIW. AI really can't be trusted!

All good points taken Ralph, 10-4.  A few members and I do discuss this part, and to your valid point - that "we've gotta hear it in our room, our system, with our speakers", unquote.  

Maybe some day I'll get the chance to hear your amps on my own custom design speakers.  I was looking for Axpona videos of reviewers in your Popori / Atmasphere listening room just for fun. Saw a few quick walk-thrus, not sit-and-listen ones, not yet.  Will keep looking.  If something shows up on YT, feel free to send a message or reply here. Not like being at Axpona, but it is fun to listen to other reviewers comments and what they saw and heard first hand. Thanks Ralph!

atmasphere's avatar
atmasphere
12,404 posts
 

@decooney There might be something from Audiophile Junkie. I checked YT and it doesn't appear to be up so far...

hilde45's avatar
hilde45 OP
5,997 posts
 

@atmasphere  @decooney I would also like to see/hear a video of the amps in action with Popori. Please do share.

Regarding decooney’s statement,

Again what I was floored about is just how many different rooms with tube amps, tube preamps, and so many other "tube" related devices after we’ve been led to believe its all slowing down, clearly not the case looking over all of the Axpona walk-thru videos too. 

I don’t think we were "led to believe it" so much as it was actually slowing down. War, tariffs, fires, and hoarding in response.

Has it picked up some? Sure. But videos of Axpona is not likely representative of the median trends. Shows and videos about shows know that tubes look cool and help the general popularity of audio.  That, to me,  is a more convincing explanation of what’s going on, overall. 

My money is on tubes becoming more niche, more expensive. Non-tubes, including Class D, seems a wise bet, still, for anyone who's selling to the wider market.

More to discover