Tommy pointed me to this thread and asked for comments. I'm not familiar with the particulars of his design, but I wanted to comment on the point about sound vs specs. It's true that there are quite a few amps that really sound nice (not necessarily accurate but certainly nice) in spite of less than stellar numbers. However, "nice sound" aside, what I can say with absolute certainty is that I've never heard a truly accurate and neutral amp that didn't have the numbers to match.
The "good-numbers bad-sound amp" is a myth that's been with us since the 80's when some class AB amps (typically Japanese with lots of lights on a black anodized front) were marketed with spectacular numbers - or so one was led to believe. Invariably it turned out that either the promised performance was only attained at 1kHz/1W or not at all. Nowadays we would describe this as "making misleading claims". When properly tested these amplifiers performed abysmally and indeed sounded the part. Those few amps that truly delivered on their promised performance still sound good by today's standards.
Simply put, the widely held belief that performance and sound are completely disjoint is a result of irresponsible salesmanship, no more no less. The relationship between numbers and sound may not be 1:1, the correlation is much stronger than is generally accepted.
We're seeing something of a rerun of this story in class D. Like Tommy I'm often confronted by people tut-tutting (invariably before trying out my stuff, never afterwards) based on previous experiences with other products. Indeed, many class D amps haven't exactly blazed a trail for the technology. But here too, those products that disappoint in the listening room do likewise on the lab bench. Again the 1kHz/1W figure may look good for many amps but it's the high power / high frequency numbers that show what an amp is made of. Output impedance at 20kHz is another neglected item. Everyone can get super duper "damping factor" at 50Hz. So what? Can they do it at the other end of the spectrum too? So what I want to say is: if you've heard a class D amp with good specs on all counts and you're still not happy - I won't argue. But if you haven't: do take the time to try one out that does measure well. Although I haven't heard or measured Tommy's amps yet, the published numbers (graphs would be appreciated!) make them worthy of anyone's attention.
BTW, I'm aware that there are also some who seem to think that class D is inherently better sounding than other technologies. I'm not one of them. I don't believe class D is either inherently superior or inferior to other technologies. The advantages of class D are all of a practical nature. Good sound can be had from any technology (not always equally easily though), the only thing you definitely can't get from other kinds of amplifiers is a lot of power with hardly any wasted energy. I know several audiophiles consciously moving towards class D simply for environmental reasons, but of course they expect their new amp to sound at least as good as the one it's replacing. This is what good class D is about, not about some "novel magic sound experience" because that's bull. If it sounds that radically different from a really good traditional amp, there's something wrong. The time of making great strides in amplifier sound is over. The time of making great amps, luckily, is not.
While I'm at it I might share my experience about price. I've tried holding my own as a one man audio company in the past and I'm still part of a 4-man endeavour called Grimm Audio. From that experience I can tell you it's a frustrating fact of life that when you're on the wrong side of the economy of scale, making stuff really gets expensive. In the beginning one is often tempted to charge too little but after a while you really find the numbers don't add up if you try to stay in the same ball park with bigger joints. So your prices have to go up. But with a higher price tag customers expect higher quality (rightly so!). And that makes it even more expensive etc. The only stable solution to this equation is at a quality level (sound, build, "exclusivity" etc) that only very few people demand (that's you folks) so that larger companies no longer have a scale advantage and instead are at a disadvantage due to greater overhead. That's where the equation tilts. Add the current price hike in commodities like copper, a weak USD and volatility of the market in general and you get a price increase that would otherwise seem, on the face of it, difficult to explain.
Apologies for excessive verbosity. I am like that.
Cheers,
Bruno (who's now leaving on vacation so unlikely to check back on this thread for the next week)
