Originally Posted by
Macca
True class A will run hotter when idling, playing music through them actually cools them down.
Running hot at idle is no guarantee that an amp is "pure" class A whatsoever. Most "class A amps" are not class A to full output as it requires such ridiculous effort and spending of money in order to keep it cool enough! Many will remember the Musical Fidelity A370 which was thought of as class A by many... although it was rated at 185WPC (and gave about 210WPC in practice), those LP record sized heatsinks, one per channel, were only enough for 18WPC to be in class A!
Generally I'd be suspicious of claims of over 20WPC or so of class A power, especially if there is no cooling fan. A cooling fan works miracles in getting rid of heat and a heatsink capable of say 20 W class A without a fan could be good for 50-60W with a fan! The problem here of course is that some people are averse to the idea of a fan due to the noise from it, but, I've found it possible to use a slow running fan in virtual silence... Due both to this, the music drowning out any fan noise and the prevalence of cooling fans in PC's and related equipment these days anyway, I don't see a fan as a big issue personally.
There are many more advantages to class A than merely getting rid of crossover distortion BTW! Pretty much everything measurable gets much better when class A is used!! The only down sides are it will be big, it will be heavy, it will be very expensive and it will use loads of electricity... If there is any interest I may come back to these things in more detail.... Technical stuff usually kills a thread though!
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