No! It’s made like this and it’ll work fine.
(Actually the best and most stabile operating temperature for many semiconductors of this sort is 60-70 degC).
Set the idle current as adviced in the service manual.
Final adjustments are done with the Beomaster under normal working conditions (warm).
If the idle runs astray (keeps increasing, also after a few minutes) there is a problem
somewhere, – most likely lack of thermal coupling from the output stage darlingtons – or from the temp. sensing transistor in the constant current generator – to the cooling fins.
(Never run an amplifier like this without the cooling fins – it’ll do a thermal runaway).
Martin