Oh how I wish Class D amps ...

I also used to own a 1970's vintage Class G Hitachi sr803 receiver for many years. Class G is an older similar but much different relative of Class D.

The Class G amp there clearly exhibited its advertised ability to deliver double its rated 50w/ch for only brief periods. THough it had some guts for a smaller 50w receiver, it did not perform as well as its true 100w/ch brethren of the time. That sound was quite meh, nothing even close to the modern bar set by the better modern amps.

Correction:

The Class G Hitachi receiver I owned was a sr-804, not an sr-803.

" Any of the class D users driving a pair of soundlab speakers;if so whats your opinion?"

A friend of mine with soundlab (latest A1) have auditioned my Wilson's Sasha driven by the pair of Spectron monoblocks and also bought the pair. (He used to have Pass Lab X350.5) I love the sound of his system and so does he.
Pass Lab, rather suprisingly for me, sounded "grayish" or "grainy" with shallow bass and very little dynamics in comparison to Spectron. I suspect this is only because these electrostatics demand power and power and power and Spectrons have about 7kW peak power.

Mike

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."