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

Have you done away with your Class A Amp due to Heat concerns?    NO

Will you be moving away from Class A Amp due to Heat concerns?  NO

Will you never buy a Class A Amp due to Heat concerns?  NO

Since the early 1990s I have run Krell KRS200s uprated by Krell to 400W per side.  They are probably about the hottest amps around and can pull down nearly 2kW per side.  Sound is wonderful of course.  It's a big room and in the basement so it doesn't get too hot.  I don't heat it in the winter as it's dedicated just to music.

As for the global warming lobby, it can go swing a cat.  In the recent COP-OUT 22 all the big countries of the world were unable to agree any positive action.  We are all too greedy and competitive.  They never agree any ACTION, they just make promises they do nothing to keep.  1.5C is already gone, measurements show we've already reached it.  Don't worry, humanity will adapt, it always has done.  Sure some will be inconvenienced, some will die.  It's always been that way.  Anyone wanting action on global warming needs to pray for a meteor hit.

@decathlon1991 

Thanks.  I knew my uprated KRS200s are big.  But I had no idea they are planetary paragons.  Thanks for this.

What we need now is a designer that can take pure Class A down to a quarter ohm.  Guess he'll be put in jail if he can do it.

Stiff and powerful rules OK.  Just going downstairs for another wonderful dose of reality.

@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.

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.

@yyzsantabarbara     No I haven't.  I am not looking much for upgrades any more and I don't go out listening to new kit.  After nearly 60 years, I'm in the lucky position that I love my system the way it is.  I occasionally buy a phono cart, mainly top-end Ortofon.  I changed my pre-amps 4 years ago from old Audio Research to vdH The Grail and Audio Research Ref 6.  Otherwise it's all old stuff.

I read Krell Solo 575 Mono Power Amplifier 575 Watt Amplifier features 'iBias'.  This is said 'to deliver the rich musicality of Class A amplifiers, the uncompromised dynamics of classic Krell amplifiers, and the efficiency and low power consumption of Class G and H amplifiers.'  Sorry.  I don't believe you can get something for nothing.  In their publicity Krell extol the virtues of Class A and pretend they are still building it.  Neither do I trust Krell since the D'Agostinos were fired.  The way that was done suggests the new owners are bad guys not to be trusted.

In 2015 they cost $22,500/pair.  Not a lot, in the context.  Fremer's 2015 review was 'equivocal', although Atkinson found it measured 'impressively'.  For those that are concerned, the power supply isn't stiff; output doesn't double up down to 4 ohms, let alone 2.

@atmasphere 

You've been taken in like all the other punters.

The Krell sliding bias system and its predecessors are cons.

The orchestra is noodling and so is the bias on the Krell.

Suddenly the guy at the back whacks the six foot drum for all he's worth.

The guy in the amp says 'OMIGOD the guy in the orchestra has whacked that drum.  For *****sake get that bias up immediately.'  The other guy in the amp on the bias hears the msg and turns up the wick.  But the guy in the orchestra on the big drum has already gone home.

YOU CANNOT UP THE BIAS QUICK ENOUGH TO CATCH THE MOMENT.

I have read the patent and it does not answer this.  It cannot.  I asked a senior engineer working on my KRS200s how it solves this issue and he could not answer.

This started as a con and remains a con.  The bias cannot be changed quickly enough.  The only way to do it would be to buffer the signal for a second or so which would introduce insoluable clock problems.

@bulldogger    Thank you for telling me.  But the day is over.  Krell had stopped building pure Class A even before the D'Agostinos were so rudely kicked out of their own company.