Tube Amp Archive

3181 is a lower freaq response than the 3131A so I read.

I have an excellent 50w BF Bassman.... I'll give it a try. perhaps I too can pop one of these. I have been checkin around and this JBL spin off from the early seventies is supposed to be.... reputed to be bullet proof. They have super high power handling capability models. these 3181a guys are suppo...

Thank you for the advice. I found that out last nite while removing resistors. I went so far as to dig out an old meter as a second check. Older and Wiser everyday. still having fun!

Thanks for the advice in this effort. I checked the guitar and ampface for sizzle and felt no stray dc at the strings, pickups, or ampface. I didn't want to leave it on long enough to probe the eyelet board. Im goin to try the new cleaners in the pots and other prescribed areas while the amp is down...

I started checking resister values. plate resistors in preamp sections are all just at the 10% limit or worse. All resistors in the phase inverter are toast. I checked all of the 5% resistors here and they are just BAD. at the 12at7 the plate 82Kohm guy pin1 reads 185Kohm; and the plate pin 7 100koh...

looking for technical info on this speaker. Cetek Guass; 3181A, a JBL spin off I believe, from the 70's. Dollar amount? Specs? I know these are 200w with some close models that handle more power. 3181A is a 200w model. Has anybody played through these with a Gibson or Fender amp. Will a BFTwin Rever...

Your not going to take that beauty out to gig are you? It is too pretty.

What I thought I said.... The 67BFSR has trannies that are.... oh what the heck. The reputed 1968 dripedge Twin was assembled before the 67 BFSR.

Thanks for the help. This is a bizarre amp. It was sold as a '68. Ahh the formative years. I have a 1967 BFSR with trannys older than this 68twin.

lookin at the tube pinout, plate resistors are 100k guys associated with pins 1 and 6. of the preamp tubes. 12ax7 for the vibrato section.. I guess this is preamp section 2. I will check em out. When you say probe the board you mean the actual board itself, the phenol or whatever it is made of; eyel...

:shock: Came across this very special amp and payed more for it than I wanted to. Took it home and immediately plugged it in, turned it on and immediately turned it off. It made more noise than any amp I have ever owned. I decided to make it my learning vehical. I have played guitar for a very long ...

The old Fender Amp Field Guide has some RedKnob schematics

Is it worth a hundred dollars?