powering down amp when changing preamp tubes

[Gary Brennan]

Is in necessary to power down an amp when auditioning preamp tubes?

gb

[VaughnC]

If your amp has a stand-by switch, turning it on stand-by is sufficient...just wait about 10 seconds for the circuit caps to discharge. Or, if your amp has a post PI master volume control you could also turn that full counterclockwise and replace a preamp tube with an amp powered up. Otherwise, there is a potential for speaker damage if you replace a preamp tube with an amp powered up due to the make/break of the tube contacts.

[Gary Brennan]

Thank you Vaughn!

gb