12 AX 7.

Sassafras

Do preamp valves need to be warmed up? I ask because I've got a buffer that uses a 12ax7 and don't want to damage it. Obviously I know nothing about the technical side of valves otherwise I wouldn't be asking.

ecc83

Well, the beardy/tweaky/audiophools might say so but in reality no.

It is actually almost impossible to damage a preamp valve electrically in  conventional circuit, even excess heater volts will be withstood for quite some time. In fact, switches and jacks are likely to fail before a good old ECCXX!

Dave.

Sassafras

Thanks for setting my mind at rest.