Class A amplifiers

coltrane1 I have a Plinius SA100 MkIII that checks all the boxes for me. Balanced or single ended inptuts, selectable Class A or AB operation, beefy heat sinks and top notch electronics. Hasn’t had an issue in the past 20 years of operation! Keeps me warm during the long Maine winters too! 🥶

emrofsemanon:
I’ve recently come a long way on my push-pull, class A, SS, tube, hybrid, SET, SIT amplifier journey.  IMHO, my SET implementation (dual Coincident 845 Turbo’s -28 watt and 94db efficient speakers) brought me closer to acoustic music than any other implementation (of approximately 25 different amp combinations- Bedini, BEL, Threshold, Muse, ARC, Moscode, Counterpoint, etc.). Terms like organic and realistic applied.  The realism of an acoustic guitar was breathtaking. However, the tradeoff was weaker dynamics- somewhat thin sounding on large dynamic swings of rock and orchestral music.  In the end, I settled on an Firstwatt SIT-3.  Nearly as good as the Coincident SET in realism, but with a far superior coherent presentation of the entire audio spectrum. I can say I’m temporarily satisfied.

The OP is asking about Levinson gear.  At least the classic era Levinsons, some of them do cook themselves to death. I have a No.23 and the repair job is going to be near $3000.  The authorized repair center explained that the Levinsons do tend to do that. 

While they are "high bias" Class-A Plinius 102 amps cannot be biased "Pure Class-A to their rated 8ohm wattage output". They run A/B.
To have those heatsinks at a constant safe 55-to 60c they would have to be approximately 4 x that size for the amp to be safe to be pure class-A all the way.
Search all you like and won’t find it stated anywhere they are Biased up Pure Class-A all the way into 8ohms, not even on their archived website.
https://web.archive.org/web/20060115165723/http://www.pliniusaudio.com/pro/pro02.htm

At a guess I would say 50watts of Class-A and the rest is B up to 125w

Cheers George

I think this should vary greatly based on thermal design and usage. No reason why a Class A amp of any rating can't be designed with enough ventilation and heat sinks to last a lot longer than that.

Is Your particular Class A amp going to last 10 years before servicing? I have no idea. :)