Handling Heavy Amps

@jfrmusic Well, let us know if you do go for the Bryston.  I bet that would be a great match & I'd be curious about how it works in your system.

Ayre makes discrete power amps, of course.  But they're a lot pricier than the integrated (the DAC module is optional).

@jfrmusic Yes, no-hashtag metoo. I have C7ES’s, lower-back problems, no local dealers, and no family members or local friends who can help me with heavy components.

Last year, I spent several months comparing integrateds for a major upgrade, with an eye on weight. I’ve had Class D amps, but have always found them to be too harsh, grainy, analytical, whatever you want to call it. I understand that newer Class D designs, which use GaN FETs, resolve many of these problems, but have had no opporutnity to hear them myself.

What I found was that the best option was the Ayre line. Ayre’s products are based on the brilliant Charlie Hansen’s adaptation of "diamond" output-stage circuitry, which produces power much more efficiently than do more conventional designs.

E.g., check out Stereophile/Absolute Sound’s reviews of Ayre's EX-8 v.2 integrated, about $10K, 300+ wpc, very broad functionaity & flexible connectivity, and including an integrated DAC that is really quite impressive for an embedded component. All clocking in at  24 pounds, most of which is the weight of the unit’s transformers.

A runner-up, that offers the same rarified class of SQ, is the Hegel line.  High-powered, beautifully designed & built, great functionality & connectivity, and even the integrated, I believe, is something like 45 pounds.

Both of these lines have a reputation for being a particularly good match with Harbeths.

If you're considering tubes, there are options like ARC’s $8500 VSi75 & $5500 i/50 integrateds, 50/75wpc & 40/37 pounds -- relatively limited connectivity, and maybe not a great match for the Harbeths' high-end, but still great products.

Bottom line is that llighter-weight products are out there, but there aren’t many.  Broader adoption of GaN Class Ds may create more opportunities this year.

I realize that you’ve been bombarded with help since posting your original message, but I hope these suggestions are helpful.

One thing, OP: What's your budget? 

I’m astounded by the volume of postings in this thread. This is one of the most popular Audiogon conversations I’ve seen in a long time.

But it’s depressing to discover that so many colleagues have the same (age-related?) back problems that I do.

I hate to stereo-type, but imaybe audiophilia really is an old man’s game.

@atmasphere

Technical papers that discuss Class D topology suggest that the distortion resulting from the topology’s dead-time constraints is similar in effect to what we used to call TIM or SID distortion in high-feedback, low slew-rate designs.

IOW, pre-GaN-FET Class D artifacts sound to the ear like intermodulation distortion when reproducing rapid rise times -- e.g., transients. It’s certainly possible for a listener to interpret this as brightness or some other relatively simple frequency-response anomaly, but I personally hear the audible effects of Class D distortion more like the complex and nuanced effects created by high-frequency power-line noise.

I realize that I’m hand-waving a bit, but I’m trying to keep this message concise without dumbing-down.

And as for me, I’m negative on pre-Gan D topology. I have 4 Class D amps in service right now and am actively trying to replace them all. Or at least relegate them to home-theater surround channels.  I realize that there are some well-reviewed D-topology components out there, but I haven't yet heard them.

@atmasphere

Having never heard your products, I could not with any credibility comment on your comparison to Class A tube OTLs. But please be aware that I’m not trying to criticize your amplifiers. I’m talking about the way that we perceive the sonic artifacts produced by most Class D amplifiers. Please reread.

I tried to be careful with my wording, stating that "traditional" Class D topologies produce distortion that is similar in effect to Aczel-period SID/TIM. But as I tried to convey, this type of distortion is caused by a mechanism distinct from the high-feedback/lower slew-rate TIM that made news back in the 90s, just as is the audible-range intermodulation distortion caused by supersonic, low-amplitude line noise. Class D and line-noise-induced IM have nothing to do with feedback. The sonic effect of all three, however (at least to my ears) is similar. And when you do a deep dive into the technology, that makes sense. That was my point.

I also understand that the much shorter dead time of GaN FET output stages can greatly mitigate this flavor of TIM distortion. Given that "Class D" is an umbrella term that desribes only one characteristic of a complete amplifier design, there have always been at least a few D amplifiers that sounded pretty good, regardless of transistor substrate. Even more so since the increased popularity of GaN FET output stages.

So when you state that your Class D amps don’t produce the types of artifacts that have long compromised D designs, I can only invite you to loan me a unit so that I can hear for myself. Barring that, please try to understand my comments in context.

By the way, I’m not sure what you’re trying to convey when you say that "the deadtime in [your amps] causes ’lower ordered harmonics’ ". One could argue that nasty third-order, and even fifth-order, harmonics are "lower." I suspect you meant that, like a tube amp, it produces even-ordered harmonics.

Hey, gotta be precise when you’re talking to lawyers and engineers! 😉

Anyway, good luck with what I’m sure is a terrific product line.  (It certainly has a good reputation.)  I'm currently looking for a sub-40-pound integrated in the $7-15K range, so if you have any suggestions, I'd certainly take a look.