Phil,
Not a dumb question at all. Your variac will work just fine.
I'd strongly suggest using an appropriate fuse between
the variac and radio under test.

Steve

Diane wrote in message
...
Dumb question, but how does it affect my old tube receivers slowly
bringing
up the voltage using my 12amp variable transformer versus a smaller one?
Is
it just overkill or is there some danger to the radio?
-Phil (not Diane)