Blowing Tubes Live.

[mARKw]

Hi. If one tube blew in a 2:90 during a performance, would one side just be operating half power? Would that be cool to continue the show or would you turn the affected side volume down and just carry on with the power from the other side....or maybe turn the affected side UP since it was half power? The tubes operate in banks of two, don't they?

I am about to buy a 2:90. I'll be using it with my JMP1. When I save up I might get a......*wait for it*......Triaxis.

Cheers

 

[disassembled]

If you blow tubes on one side of the 2:90 you can remove two of the inner or outer pairs for that channel and then reduce your impedance by half. If you blow 3 tubes of 1 channel then I do not recommend using the amp anymore until you get it serviced. You should never gig without a backup so try and pick up a used solid state power amp to be prepared. I would rather have a slightly worse tone during a gig then to have a possible destroyed power amp.

 

[JamesD]

I would agree. It is always nice to have something there as backup, be it tubes or another head.

 

[mARKw]

Thanks for the replies.

Hypothecically, If you took out all the tubes on one channel and turned the volume down on that channel and the presence up and didn't connect and input into that channel, would that be safe.

No doubt that sounds crazy, I'm just curious.

You know what they say - There's no stupid questions......just stupid people. (Like me)

Cheers

 

[Russ]

Why not just bring a full set of tubes as spares to your gig and not worry about that kind of crap? It only takes about a minute to get the fresh ones in and you are back to playing (you will only lose about a song's worth of playing time). Or bring a backup if you feel like the extra weight. I usually carry a bag of emergency spares and stuff. It includes strings, cables, tubes, fuses, flashlight, etc. If you have a roadie, let him take care of it. If you don't have a roadie, or even if you do, maintain your bag as if it were any other piece of gear that you own. If your amp goes through all the spares then your exercise regimen of bringing a backup might prove handy. Do not continue to play on an amp that is obviously having issues. Take it in for service.

 

[disassembled]

Do not run a tube amp without tubes in it (other than for testing purposes). You are better off just bringing a small 1 space solid state backup amp (like the ADA amp) instead of trying to mess with bringing backup tubes that could possibly break in transport or cause more problems if they are not matched to the rest of the tubes. It can be tough finding/replacing a bad tube in a noisy club and you probably raise the risk of breaking something by just being in a rush. If anything just make a deal with another band to use their gear incase yours takes a dump on you.

 

[mARKw]

Cheers guys. I know it was a stupid question - This was just hypothetical to help me ( and hopefully others ) get a better understanding of this whole deal.

Our singer blew a fuse the other night because he accidently switched something on the back of his speakers so one side of his 2:50 wasn't connected to them. Oops. He just continued singing so it was still a cool gig.

I would probably get away with stealing his rig off him and let him sing without playing guitar.. but still, I should get myself some spare fuses, etc...

Thanks for the replies.

 

[Paul Secondino]

Hypothecically, If you took out all the tubes on one channel and turned the volume down on that channel and the presence up and didn't connect and input into that channel, would that be safe.

it would be best to leave that side of the amp in standby mode and not remove the tubes at all. Some amps only have 1 main standby switch for both sides of the amp but the 290 has 1 switch for each side I believe.

 

[mARKw]

it would be best to leave that side of the amp in standby mode and not remove the tubes at all. Some amps only have 1 main standby switch for both sides of the amp but the 290 has 1 switch for each side I believe.

(Unfortunately) The 2:90 only has one standby switch which controls both sides.

 

[Rayder]

the left switch is to power it up, and the right is the standby switch