Power amp Tube Question

[EdgeOvThorns]

Hey , a friend of mine asked me to post about his mesa 90:90. He wants to retube before his next gig but is unsure about having to bias. I may be wrong but arent mesa amps built with a fixed bias? Basically need to know if its plug and play. Thanks.

 

[kmoed]

Yes the have a fixed BIAS. Nothing to adjust just pop in the new tubes.

 

[Timbre Wolf]

Yes the have a fixed BIAS. Nothing to adjust just pop in the new tubes.

You can do this with Mesa-branded tubes, but not others. Fixed-bias is basically adjustable bias, without the adjustment option, and tubes that run current outside of the Boogie spec. range will not function properly.

- Thom

 

[EdgeOvThorns]

Thats all I needed to know. Thanks for your help guys.

 

[congalocke]

Timbre Wolf,

I have enjoyed reading your post about tubes for the Triaxis and want to take this opportunity to say THANK YOU SO MUCH!

From your post here I am thinking that Bias only has to do with power tubes and not 12AX7's???

Can I pop in 6L6 Groove Tubes for my 2:90 without any problems or do I need to stay Mesa in the power amp section?

Thanks for your time
conga

 

[Luijo]

Preamp tubes are self biasing, so no need to worry about them.
If you want to go the GT route you sure can, you just have to call them and ask for a set for a MB amp and they'll set you up just fine. I've done that for a few friends with no probs.
I guess if you call MESA they'll tell you otherwise. :wink:

 

[Timbre Wolf]

Timbre Wolf,

I have enjoyed reading your post about tubes for the Triaxis and want to take this opportunity to say THANK YOU SO MUCH!

From your post here I am thinking that Bias only has to do with power tubes and not 12AX7's???

Can I pop in 6L6 Groove Tubes for my 2:90 without any problems or do I need to stay Mesa in the power amp section?

Thanks for your time
conga

De Nada! :wink:

As for the other questions, Luijo has already answered them very well.

- Thom