hot & cold tube swapping?

[JamieMcC]

As a newbie to tube gear and rolling I would like to know about swapping tubes on the Crack do both tubes need to be cold or can you roll a cold 12au7 into the amp with a hot 6080 or vica versa?

 I would like to get it right from the start cheers.

[Grainger49]

When you roll in a cold tube it will take about 15 minutes to sound its best.  If you roll back a recently removed tube it will warm up faster.

It doesn't matter if the incoming tube is still warm or cold as far as safety is concerned.  It only makes a difference as to how quickly the tube will sound its best.

[JamieMcC]

Thanks Grainger, the perfect answer.

[fullheadofnothing]

HOLD ON ONE SECOND. Hot swapping is a term that has a meaning, and it is crucial to be clear here. Tubes aren't USB devices...

If you mean "do I need to turn off a piece of gear before removing a tube?" YES. ABSOLUTELY YES.

NEVER PULL A TUBE FROM A LIVE PIECE OF GEAR.

NEVER TURN ON A PIECE OF GEAR WITHOUT A TUBE AND INSTALL A TUBE TO LIVE VOLTAGE.

If you're referring to temperature, then, whatever.

[JamieMcC]

Yes I was referring to temperature, I am please you added your comment as its a very important and valid point for those of us who are new to tube amplifiers. Its very easy to assume most people would switch off and if they did not know this then common sense and caution would lead them to that decision. However common sense is not always dished out equally and we can all be found wanting at times. So its a important thing to know from the start.

Cheers