The SA250 does run very hot in class A. A scorching 160 degrees which is HOT HOT HOT!!! By comparison, even the Class A Krells run at a "tepid" 140 degrees.(That indeed HOT! to touch) I never ran my SA 250 ( MkI original version) in class A for more than a few hours at a time. But, I never experienced any problem with the amp shutting down. My room size is fairly large and opens into the rest of the house, so I think it had good ventilation. I dont know if your amps location and in what room size, ventilation ability, ect..is causing it to run hotter than would be expected, but you are apparently tripping the thermal safety devices designed to protect the amp( a good thing)... and keep it from baking in its case.
It may be that you could set a small quiet running fan behind the amp to help. FWIW, I rarley ran mine in class A, as I found most casual listening extremely good in AB.
Good luck.
It may be that you could set a small quiet running fan behind the amp to help. FWIW, I rarley ran mine in class A, as I found most casual listening extremely good in AB.
Good luck.