Oh how I wish Class D amps ...

Soundlabs don't actually need all that much power, but transistor amps (including class D) have trouble making power into the impedances of the Soundlab. Its for this reason that people using transistors tend to use very high power amps with them.

For example if you have an amp with 600 watt/8 ohms, on the Soundlab the amp will make about 150 watts. IMO/IME 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.

"First off, the Ref 1000 is not a 1000 WPC amp, it is a 500 WPC amp (but that is really only for peak/short periods, not continuous)."

REF1000 is rated 1000W/4ohm. By "short periods" only you probably referring to specification of Icepower module 1000ASP used in REF1000 showing only 150W FTC?

First of all in reality it is much better than that (attached test below conducted by DIY member - read below), second of all it is rating of the module WITHOUT ANY HEATSINK!!! REF1000 uses heatsink and I suspect can output 1000W per FTC requirement but it is not even necessary because average music power is only few percent of the peak power.

Originally posted by dmfraser
"I operated a sample 1000ASP on the bench delivering 350W average of pink noise into a 4 ohm load for over one hour with no additional heatsink and the metal case stayed below 55°C.

However, higher levels would make the power supply voltage go down to act as a thermal compensation. Much nicer than just shutting down.

However, with 1214W of sine wave, partly into clipping, after about 35 seconds, the output level would drop to about 600W by the protection circuitry. Remember this is with no additional heatsink."

Ckoffend - I might be wrong about heatsink since they talked about ADDITIONAL heatsink (module has its own) but I don't really know If REF100 has additional heatsink (picture shows some heatsink).

Continuos power rating doesn't make much sense anyway since average music power delivered is only few percent of the peak.

"Atmasphere, OK. But FWIW, there should be no problem with almost any preamp, tube or transistor, driving a class D amp.

From my non professional experience. I was immediately taken by my first switching amplifiers lack of fatigue and its unusually transparent presentation. It did, however, pose some difficult issues regarding RF and/or EMI. An afternoons worth of a VAC upgrade and the RF issues were resolved. Now I was hearing my tube preamp, its noise and sonic colorations. After some extensive auditioning I found my current battery powered solid state preamp to be a key partnering with my switching amplifiers technology.

I agree, there shouldn't be a problem with other preamps and to a great extent there aren't. Still, the isolation of a battery powered pre proved to be a surprising sonic advancement in my system. Partnering the H2O with the Fire pre is another example.

I'd like to mirror Muralman, switching amplifiers require system refinement to varying degrees. Cable materials and size, shielding, and VAC supply all play a large part in system refinement.

All my amplifiers have their shortcomings but the switchers have far less. They are different and they do have their own presentation. None that I've auditioned even come close to sounding like a tube amplifier or solid state.

I'll add that my OHM F5s are about as power hungry as they come. I bought the Bel Canto ref1000ms as a low or no compromise solution for reasonable cost. I like to play music that should be loud, loud. The BC has fit the bill perfectly. They are the first amps I have tried (of 3) that have never run out of steam no matter what I do. THe music just continues to expand and inflate as I increase the volume to whatever high level might be needed. No signs of stress or distortion and one often does not even realize how loud things are until you try to hear somebody near you talk.

I cannot find any fault. Some might prefer a more lively top end I suspect, but the top end is all there quite nicely. That's about it.