Hi Mike,
Yes, I agree with your "less heat=longer life" thought, but only with everything else being equal. And I want to believe that the engineers at whatever brand that runs hot know that much.
When it comes to the issue of an amp's heat handling, I think we have to consider two different things:
(1) How much heat is, by design, generated by the power-stage transistors (and other components), at various power output levels.
(2) How well the generated heat is dissipated.
I do not have any hard data here, so the following is all my speculation (something I really don't like
). But I just cannot believe that the differences in the operating case-surface temperature is all ascribed to (2), i.e., a severely inferior heat-dissipation design in the hot-running brands. The consensus seems that, for example, Onkyo and Denon generally run cool, whereas Pioneer can get very hot. But does this automatically mean that the engineers at the latter brand care less about heat and try to skimp on thermal management? Umm... not very convincing to me.
Just as a side, among those 4 models I listed above, H/K and Pioneer, the two allegedly hot-running models, are in fact heavier than the other two. Where do these brands invest that additional amount of metals? I do not know...
Well, I start to realize that these comparisons only confuse me. And, to be honest, I seriously doubt that I can hear a clear difference in sound quality among these models (unless I have a chance to do a true A/B testing at my home, which I do not think I can). I already know from my casual auditioning at local stores that all these brands at this price range sound, well..., wonderful.
So, after all, I guess I will have to decide based on factors that are obvious, including functional features, appearance, and the ability to drive various loads properly, etc... Operating temperature will unlikely be my primary criteria. I do not think they are that stupid...
Sorry for this confused, vague post...
Cheers!
