Oh how I wish Class D amps ...

"No signs of stress or distortion"

- that might be due to line and load regulated power supply in your REF1000."

I'm thinking that is a part of it. At least I'm hoping so because I know that is the main reason I opted to pay a hefty premium for the BC ref1000ms rather than go with other similar designs for a lot less.

Mapman - second generation of REF1000 not only have huge bank of additional capacitors but also converts huge narrow spikes of current to more of resistive load. Was it worth extra price? I'm sure it was. Any small improvement at this point costs a lot and is worth any money if you know that it works in your system. I might upgrade to this amp in future. I understand that "m" stands for mk II (new generation) but am not sure about "s" suffix?

" ...the bar that has to be met by class D is not how they compare to traditional transistor designs but (especially on SoundLabs) how well they compare to tube amplification. "

Hello Athmaspere. I don't like to put all amps together into single group as "class D" and even more tube amps.

I mentioned in my post Spectrons and Wayne Donnelly, reviewer from Enjoy The Music, sent back his $50k VTL Zigfrieds (spl) when he got his Spectron. I also much prefer Spectron over my former amp, McIntosh 2202 etc

On other hand, I truly love OTLs - your and that of Jud Barber of Joule-Electra but I can't stand their heat and high maintanence. Moreover, only you know how well your amps can drive Soundlab (I suspect very well) but 100% they cannot drive my Sasha by Wilson and provide the same dynamic range as Spectron does - Sashas are the most power hungry speakers in entire David Wilson line.

Mike

Mike do you think Ralph's MA2 or MA3 could drive those speakers?

I've owned several variants of TA2024 including Trends 10.1, a few TA2020 amps from Muse, Topping, etc, and currently use a LM1875 from Brian Bell (chipamp_dot_com.)

This last one is a pure gainclone, minimalistic, very few parts. The best 20wpc I've ever heard from solid state, and better in most ways than many single-ended triode and pentode 6BQ5 amps. I've owned Almarro, Decware copies, rebuilt vintage SEs by Magnavox, Motorola, Zenith, some killer DIY 6bq5 SE using a chip voltage regulator and tube rectifier, and lots more. I've also owned many rebuilt vintage tube amps from EICO, Fisher, Scott, Pilot (SA232 is AMAZING) Allied (6BM8), Conn Organ (6L6), Harman Kardon, etc. I've owned solid-state by Belles, Van Alstine, Nelson Pass, Dynaco and much more. Pair a well-designed class-d with good speakers from Tang Band, Fostex, Mission, etc and they are near perfect, IMO. Great amps have been around since the 1940s. I think even a basic run-of-the-mill Class D will out-perform any Mosfet amp at any price. More accurate midrange, better bass, nicer higs, less audible distortion, lower noise floor, better reliability.

We are in the second "golden age" of audio. If your class-d doesn't sound like tubes, add a tube buffer between your passive attenuator and amp. For me, though, musical truth and emotional experience is more important than nostalgia.