"On separate issue, would all that heat for 24/7 at full power take toll on the circuit board? Of course the counter arguments would be the on/off as you said, and the expansion/contraction fatigue cycle due to the hot/cold."
Spatine - the only perishable component inside of SS amp is electrolytic capacitor (other than ON/OFF switch). Rush current does nothing to electrolytic capacitor other than heating it slightly (very short time and very low ESR) in spite of large momentary current. Electrolytic caps die of dehydration. Each increase in temperature of 10 deg Celsius cuts their life in half (water evaporates from electrolyte). Eventually drier capacitor has higher ESR and starts heating up to the point of runaway. In critical application (lots of current) they get to thermal runaway and explode (they have fuse to relieve pressure). The other way to damage them is to leave them without voltage for years. Aluminum oxide layer that serves as isolator is eaten by electrolyte but presence of voltage builds this layer back.
Fairy tales about rush current (turning ON) damaging equipment comes from two sources. First is the bulb or tube that breaks on power ON since cold filament has many times lower resistance. Second is the fact that if you do anything around your amp like for instance moving speakers while amp is OFF and create short it might damage amp when you turn it ON and you will blame turning ON (rush current).
Sometimes also mechanical component tends to break at start-up like for instance computer's hard disk.
Circuit boards, resistors, film and ceramic caps, transformers etc last forever even in extended temperatures. As for semiconductors - as long as they operate at sensible junction temperature (let say under 125 deg C) they also last forever. There are electronic circuits with semiconductors being turn ON/OFF hundreds times a second and they last for over 25 years. Simple example of it is seven segment multiplexed display.
As for sound being optimal after a week of continuous operation - it's possible. I don't have class A amp, don't have experience with them and perhaps less than "golden ears".
People who calculate reliability are probably ready to kill me for saying all this but statistical analysis they use is something else. When I walk with my dog we have statistically 3 legs each. Also statistically tattoos are causing motorcycle accidents.
Spatine - the only perishable component inside of SS amp is electrolytic capacitor (other than ON/OFF switch). Rush current does nothing to electrolytic capacitor other than heating it slightly (very short time and very low ESR) in spite of large momentary current. Electrolytic caps die of dehydration. Each increase in temperature of 10 deg Celsius cuts their life in half (water evaporates from electrolyte). Eventually drier capacitor has higher ESR and starts heating up to the point of runaway. In critical application (lots of current) they get to thermal runaway and explode (they have fuse to relieve pressure). The other way to damage them is to leave them without voltage for years. Aluminum oxide layer that serves as isolator is eaten by electrolyte but presence of voltage builds this layer back.
Fairy tales about rush current (turning ON) damaging equipment comes from two sources. First is the bulb or tube that breaks on power ON since cold filament has many times lower resistance. Second is the fact that if you do anything around your amp like for instance moving speakers while amp is OFF and create short it might damage amp when you turn it ON and you will blame turning ON (rush current).
Sometimes also mechanical component tends to break at start-up like for instance computer's hard disk.
Circuit boards, resistors, film and ceramic caps, transformers etc last forever even in extended temperatures. As for semiconductors - as long as they operate at sensible junction temperature (let say under 125 deg C) they also last forever. There are electronic circuits with semiconductors being turn ON/OFF hundreds times a second and they last for over 25 years. Simple example of it is seven segment multiplexed display.
As for sound being optimal after a week of continuous operation - it's possible. I don't have class A amp, don't have experience with them and perhaps less than "golden ears".
People who calculate reliability are probably ready to kill me for saying all this but statistical analysis they use is something else. When I walk with my dog we have statistically 3 legs each. Also statistically tattoos are causing motorcycle accidents.