My original post starting this thread explained that the (stereo) spec is: 1.2KVA and 300,000u.
Somewhere in the twists and turns of the thread I decsribed the monoblock as being 600VA and 300,000u. Of course, that should have read 600VA and 150,000u. My silly mistake.
Yep, there is space (just) for 600VA - it's actually arranged as 2 300VA transformers. The intention is to independently rectify and feed each half of a balanced configuration arranged on 2 signal boards (hence 2 heatsinks per monoblock).
And finally, I'll come clean. Yes, it is a fan cooled arrangement. I've simply not mentioned it up till now because of the derision which seems to meet the idea of fan cooling whenever it is raised on the forums.
Personally, I feel fan cooling has had a bad press from the audio community and implemented correctly, is the answer to most class-A heat dissapation headaches.
Yes, fans are often noisy (Purchase a low noise fan)
Yes, a poor implementation can leave you injecting noise into the system (imlement some decent isolation for the power supply - incorporate it into the regulator even!)
Run the fan at a lower voltage. (Noise tends to increase logarithmicly with fan motors, running them at half voltage works a treat)
Finally, isolate the fans from the heatsinks and the chassin with an appropriately large guage of sorbothane or similar, to finally kill any remnants of noise.
I tried this out of desperation about 7 years ago, just accepting that the end result would probably be noisy, but that it was the only way to get my high bias power amp projet at the time on the road.
The end result (complete with sorbothane mounts, etc) astounded me. For about 5 years now, I've been using some truly incredible 12db fans from Papst (sorry, I don't have the web address, but they won't be hard to find). These really are the icing on the cake and surely it's just a matter of time before Class-A afficionados release that as long as class-A amplification is associated with scalding hot mini power stations dominating peoples homes, it will never reach mass acceptance. Fan cooling is the missing link, in my view. Unfortunately, it will only shake off it's unfair reputation as unthinkable for high end audio, when others on this forum are far-sighted enough to point out that it has generally been poor implementation that has led to the audiophile 'truth' that fans are too noisy for high end audio.
Now that should put the fan-cooled cat amongst the scorched pidgeons...
While I'm at it, why doesnt someone (with far more technical ability that me) come up with a nice little schematic that solves most peoples electronic objections? I'll certainly post mine as soon as I've got to grips with just how to do it!
