How hot is too hot?


I've noticed something in my classic vacuum tube amplifier rebuilds that has puzzled me for years.
In the sets where I have replaced all filter, bypass and coupling caps, it seems that the power transformers
continue to run very warm to the touch.
With everything operating per factory specs, regardless of brand or tube count, how hot is too hot?
ampx61

Showing 1 response by aball

When I rebuilt my MC240, the power transformer temperature went up a good bit. When I put my hand on it before, it was very warm but I could leave it on there all day. Now, it gets too hot to leave my hand on it for more than 30 seconds. but my bias was way off before the rebuild.

Humans are much weaker than wires/insulation and cores, so I don't think there would be any read degradation unless temperatures approached the curie temperature of the core (often >100C). I am sure your amps are no hotter than that!

Arthur