Ditching Class A Amps due to Heat - Sort of a Poll

@earthbound 

+260,000      Why?

Well said !!!    The single most relevant, important post ever on this forum.

You have no children!

Nor do I.

At population replacement rate, those with children will have brought 131,000 more people into the world within 500 years, all consuming resources and energy.  Then the next 30 years will bring 128,000 more.

I will have brought.......none.

It doesn't half shut up the tree-huggers who complain about my big house, big old cars, big hi-fi etc.  They have nothing, NOTHING to say.  Their progeny will pollute the planet for ever or until a big meteor hit, a nuclear holocaust or the sun expands, whichever comes first.

As it happens, Class A has been on my shopping list lately. So my answers are ’no’ to all three questions. But energy consumption issues do factor in.

As others have mentioned, various manufacturers use plateau bias to reduce typical class A power consumption, including Krell obviously (they’ve done that for a while). An Evolution 302 is probably the sweet spot for me (might stretch to the 400 mono pair, you never know). But it will have to be e-series, with the 2 watt standby, not the previous model, which uses ~60 watts just sitting idle. A pity, because there’s a very tidy and wicked looking black 302 (non-e) listed on the ’Gon right now.

The new one should use less energy that my current KAV-series Krell, which is AB but doesn’t have an efficient idle/standby. I'd be curious to see how a Purifi-based amp like the tidy units Mr March makes (I'm in Australia) would sound. But I'd need to hear one, last time I tried a modern design (LLC power supply, negative feedback) the sonics were disappointing.

We pay over the base market offer for 100% green power, but still factor energy efficiency into purchasing decisions. For most anything that uses significant power. There’s no need to be a f*ckwit.

Sorr @axo1989   New Krells are NOT pure Class A.  So called anticipator circuits don't work  So called plateau bias doesn't work.  No short cut to good sound.  No free lunch.

@clearthinker

Sorr @axo1989 New Krells are NOT pure Class A. So called anticipator circuits don’t work So called plateau bias doesn’t work. No short cut to good sound. No free lunch.

I didn’t mention new Krell, Evolution series are D’Agostino designs (even though the e-series appeared after he and Rondi were forced out). And sustained plateau bias (and active cascoding) works—obviously—in the sense that it does what it’s designed to do, prevent notch distortion (the basic reason we want Class A) while reducing power consumption.

But if you want to argue that isn’t pure Class A, fair enough. I can change my answers to no, no and yes, respectively. Unless I change to high efficiency speakers and a low powered amp (and accept the tedium of constantly switching the damn thing off and on again) I’d steer clear of old-school Class A.

But while you're there, and since you are obviously into it, do you think the really old Krells sound better than the ones I have in mind?