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 , I'm not talking about the more expensive Laiv monoblocs, but the cheaper Chorus versions, coming in at about $2K for both.  I read somewhere that when compared, the Chorus monoblocs were not embarrased by the larger ones.  Based on my experoence with just one, I am not surprised.

@doni , Could you please say a bit more about how the Laiv Chorus amp compares to the Atma-Sphere monos? I recall reading that the Laiv is perhaps more sharply detailed. I'd appreciate hearing your comparisons.  I've listened closely to the Atma-Sphere amps at a dealer and was very impressed with them. For context, I currently use a custom SET amp using the 807 output tubes that puts out 8 watts; speakers are 92db efficient with simple crossover and benign impedance curve. Thank you.

My own experience with Class D amps (Devialet and Teac) is that while the soundstage is plenty wide, it was as flat as a pancake; no depth. Nothing remotely like my MSB S-200 amp. I was hoping to find something that would be just about as good but a lot lighter (I could lift the 85 pound MSB 10 years ago, I no longer can) which is why I tried these out. Those AGD amps seem very intriguing and I'd love to hear them, but even Steve Huff, who had a rave review of the Allegro very recently, seemed to go no farther describing soundstage depth than 'pretty good'. I don't know if this is something intrinsic to Class D amps or not. 

My sense is that Steve Huff raves about everything. He also sells contact with the dead. I kid you not. This is why I have no reason to ever bother listening to him about audio. He's a charlatan.

Huff's website: "Each month I call out to names of members and their loved ones on the other side in hopes of receiving a message from Heaven for you. Over the last six years we have received hundreds of pure validations from spirit for members. It has been incredible! This for me is what it is all about. Helping others, receiving messages from beyond and even helping the souls connect with their loved ones who are still here on earth.  Our soul never dies, it merely transfers to the afterlife from our body when our bind fails us as it is designed to do."

@adamay, I cannot verbalize the differences in pieces of equipment like many here, especially since my usage of these two Ganfet's is in different rooms, with different sources, DAC's and speakers.  Also, my expectations in these rooms is not the same.  I will say that I think if cost is not an issue, then go with the Atma-Spheres, but if it is, you won't be disappointed with the Laiv's.  When I get a second Laiv Chorus Ganfet, I will try to use them in the same system as the Atma-Sphere's, and then offer some thoughts.