Other comments well taken, I have in the past simply dropped in the
octal, solid-state replacements into various equipments without any
undue effect(s)... or so it would appear. Having said that, I no longer
convert to solid state, nor build up power supplies for older/surplus
equipment without the ability to turn-on filaments first. The original
tubes are still cheap and readily available. What I have found is that
if I run my vintage equipment at the rated input voltage (typ 110v) via
variacs in my distribution bus, I do not have the heat problems I did
when simply plugging them into my house 125v service, directly. The
heat difference was quite amazing!