No speaker connected when amp is on?

[tony777]

Look at this picture of John Petruccis amps in studio preparing for the next album.
No speaker is connected on three of four amps when ther powered up.
I always thought it was a big no no and would harm the amp or tubes, but maybe as long as the amps are in standby mode it doesn't matter.
Any opinions out there?

 

[HBob]

Very weird. I've always read you can only have a speaker or a dummy load connected when the amp is on or you'll damage the transformer. Or some such amp part.

Does it look to you like he's running triode, simul-class and harmonics on the three switches?

 

[sduck]

My guess is that there's a skilled engineer involved that's switching the non-speakered amps into standby as needed.

 

[snorkel54]

I'm surprised nobody has a answer to this, and why it is so... For me the logic explanations is that the power tubes is disabled, meaning that there is no signal to the speaker. But I'm sure not gonna try that with my amp :-D

 

[tony777]

For me the logic explanations is that the power tubes is disabled, meaning that there is no signal to the speaker.

I've been thinking the same, hopefully someone can confirm this.

 

[MrMarkIII]

Yes, at standby the tube is disabled. There's no high voltage supplied. Only the heater gets juice, to keep the tube warmed up, ready to play, on standby. This is why you warm tubes up in standby before playing, so the cold tube doesn't get hit with the high voltage immediately.
Even with the amp "ON" with no speaker connected, I doubt damage would occur until you actually played some guitar through the amp.

 

[Whoopysnorp]

Yeah, what I've always heard is that it's fine to do this if the amp remains on standby, and even if the amp isn't on standby as long as you can be POSITIVE there's no sound that's going to try to come out of it. Of course, the best way to be sure about that is to keep it on standby.

 

[snorkel54]

What stripe is the mark iii in the picture??

 

[McBarry]

Maybe I'm OCD..

I always have a load connected..
Removes any chance of misadventure.. and with a stack like that, and more options, another layer of potential error exists..
If it's not a spkr, then a dummy load.
My ritual is check spkr connected when the power lead is reached for. Even in my combo's.
Although I've never actually killed an O/T and hope I never do..

Dave