1967 AB165 Bassman Head

[NickC]

Have you checked the bias-balance circuit?

I removed the AB-165 style bias-balance circuit on my '66 Blackface Bassman and replaced it with the earlier AA864 blackface era "true bias".

[img]http1728]http://homepage.mac.com/swamptone/Bassm ... Modded.jpg[/img]

[img1728]http://homepage.mac.com/swamptone/A-BassmanBoard.JPG[/img]




Some good Bassman info here:

http://acruhl.freeshell.org/mga/main/AA ... AB165.html

Hope that helps.

[philo43]

Hey guys, I haven't really thought your problem out, but I had a SF Twin that was burning up tubes one-at-a-time and it turned out to be an open ground wire on the board (I can't remember which one). Is the board warped? I haven't seen many older fender fiberboards that stayed flat over the years. You might just re-heat all the eyelets and solve your problem without ever knowing what was truly wrong. Not quite as satisfying as a good troubleshoot but hey...