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

As to the sound reproduction, I think, so far, Class D does not outperform class A/B and class A. 

@niodari I've not found that the case at all. Class D has proved itself able to keep up with or surpass the best of class A or AB. Its all in implementation. 

Over the past few years I've worked through a fairly wide range of amplifiers — Atoll, Akitika, Van Alstine, Sun Valley, and several others — each with genuine strengths and each ultimately pointing me toward a clearer sense of what I actually value in reproduced sound. When I landed on the AGD Audion monoblocks, something clicked that hadn't quite clicked before. 

What the AGD does particularly well is resolve the leading edges of transients without hardening them, maintain tonal density in the midrange, and deliver bass that is both tight and texturally informative rather than merely present. Imaging is precise without feeling artificially etched, and the overall presentation has a coherence — a sense that the music is arriving as a unified event rather than as layered components — that I found absent or only partially realized in earlier amplifiers. I have a strong sense that the amps by @atmasphere  would also fit this description, but I still need to try them.

But I think the more honest and useful observation is this: these comparisons only mean something once you've identified what you're actually listening *for*. Dynamics, precision, tonal color, soundstage depth and width, micro-detail retrieval, low-frequency control — these are separable dimensions, and different amplifier topologies genuinely do different things better. A well-implemented tube amplifier may do things with harmonic texture that solid-state doesn't. A high-bias Class A design may have a particular ease at low listening levels. The sweeping judgments — "Class D sounds sterile," "tubes are always warmer," "solid-state is always more accurate" — collapse distinctions that matter.

What I found is that once I was clear about looking for a certain (and different) cluster of priorities, the AGD wasn't merely competitive with amplifiers costing considerably more. In the areas I weight most heavily, it was superior. Other Class D amps I tried were not. What results is the *lack* of an overall verdict on Class D as a category. Instead, what I got is what atmasphere points out -- that one arrives ats a verdict on *some particular* implementation, evaluated against *my* preferences, in *my* system. Which is, I'd argue, the only verdict that actually means anything.

@atmasphere 

Class D has proved itself able to keep up with or surpass the best of class A or AB.

Agree. I think that discussion was over years ago. I'd even say at least a decade ago and 'reproduction' doesn't get more accurate than class D. I use Hypex,ICE, Purifi as reference for comparisons, but it does not mean I like reference. It's all subjective preferences now.

@earthbound, thanks for sharing your experience.

I haven't gone back from class D for almost 20 years. When you lived in an apartment with no air conditioning and a pet indirectly died of heat stroke, you get to have an opinion of class A and AB.

@hilde45 

Would you mind saying why you are sticking with the Pass? What did the others offer you that the Pass did not, and what does the Pass do that the others do not?

Without going into too many specifics (it's been a while and I'm not the best at remembering things much less descriptions) I feel like my Pass setup has more authority and richness. It is balanced just the way I like, not too bright, not too dull, plenty of warmth and weight but not too much. So it fits better to my preferences than anything else I've tried. 

Part of this probably relates to me also using the Pass XP-32 preamp which is really well matched to my XA60.8 amplification. So it likely pairs better than other amps whether class A or D etc.