Retubing my mesa dual rectifier

[bemorgue]

I just retubed my pre amp and power tubes with the package from humbuckermusic.com. (http://www.humbuckermusic.com/mesa-boogie-dual-rectifier-retube-kit.html) and after replacing all the pre amp and power tubes my amp feeds back more than ever. I know it shouldn't be a biasing issue, but i'm wondering if it could be microphonics or something totally different. Any ideas as to what it could be?

 

[Addictedtokaos]

Maybe try putting your preamp tubes back and leave your new power tubes in. If you get the feedback you know its in your powertubes, if not then replace one preamp tube at a time.

 

[elvis]

Could be a bad capacitor. New tubes (with higher gain) might make it even more unstable.

 

[knotts]

I would say preamp tubes. Most likely the V1. Surprising that a mesa branded tube would cause the problem.

 

[Gnarkill3k6]

Probably a pre-amp tube as stated before me... but, what pickups (in your guitar of course) do you use? Any overdrive/distortion pedals in front?