Depending on which amp, i.e. the larger number of output tubes used, the hotter the amp runs. I have the MA-2's which consists of twenty 12AS7's per mono-block. Hot, at times, is an understatement. I live in Wisconsin, so a good portion of the year temperature is a non-factor. The only other A-S amps I have heard are the MA-1's. Fewer tubes, less power, less heat.
Regarding tube replacement, the drive tubes, 6SN7's have a reputation as long running, consistent sounding and reliable; especially NOS. The outputs....not so long, but not all that expensive.
My amps, nor the other two I have personal experience with have ever had reliability issues. Do take Scifi's suggestion and research either ASOG or threads on Audio Asylum.
The amps are very impressive. Well worth investigating.
Regarding tube replacement, the drive tubes, 6SN7's have a reputation as long running, consistent sounding and reliable; especially NOS. The outputs....not so long, but not all that expensive.
My amps, nor the other two I have personal experience with have ever had reliability issues. Do take Scifi's suggestion and research either ASOG or threads on Audio Asylum.
The amps are very impressive. Well worth investigating.