Do I have to pay someone to change my amps tubes?

[frank_1]

I have never changed tubes before, I was wondering if I were to change 6l6 tubes for a different brand 6l6 tube, do I still need it to be re-biased? Is there anything else I should know?

Thanks.

[mikedaul]

what kind of amp are you using? Some amps need to be rebiased when re-tubed, and some don't. The amp will still work either way, it just might not be performing optimally. fwiw, I think groove tubes are a rip off - but I like their system of grading tubes in a generic way, so if you buy "xyz" rated tubes and get your amp biased to them, you can go to banjomart and buy a new set of "xyz" rated tubes and pop them right in with peace of mind. You can do the same thing on your own by just buying matched sets that fall within a certain ma range.

some good links:

www.firebottle.com
www.firebottle.com/ampage/

[frank_1]

It's actually a Peavey Triple XXX amp, I have new JJ tubes, which I would like to put in place of the original tubes in the amp right now. I didn't buy the JJ tubes, but the person from whom I bought the amp from said the JJ tubes were matched.

THanks for the reply!

[mikedaul]

the xxx has built-in bias test points on the back panel. I think the bias adjust knob is behind the panel, though. So, basically you can hook up a voltmeter to the test points and adjust the bias to match the ma rating of your matched set of jj's. Don't do this if you don't feel comfortable, though. It's worth $50 to pay an amp tech for peace of mind.