Quick question, about Cabs and Ohms. . ..

[nonamemx]

Im currently experimenting with tone. I have a Marshall JCM 800 combo (open back) and a JCM 800 closed back 4x12, and Im experimenting with whether I prefer just the 4x12, or the 4x12 with the combo's speaker running too.

Should I power the amp off before unplugging the speaker, and setting the impedence switch on the back? or can I just flip it to standby?

Thanks.

[Soloist1]

Re: Quick question, about Cabs and Ohms. . ..

Absolutely. If you don't have a load plugged to a tube amp and turn it on all hell will break lose. Also make sure the switch is set for what the cab is wired for. Definitely don't change the impedance while running. You could kill your tubes or even worse your transformers.

[Chuckracer]

Re: Quick question, about Cabs and Ohms. . ..

You don't need to turn the amp off, just flip it to Stanby. This cuts the voltage to the plates and shuts off the output.
You can then switch whatever you want with no worries. Having an amp on stanby with no speakers plugged in will not hurt a thing.

[nonamemx]

Re: Quick question, about Cabs and Ohms. . ..

Alright, thanks.

Thats what I was thinking, that it shuts off the power to the speakers, I just wanted to be sure.