Deluxe Reverb to BF
          specs



It's fairly easy...
 
Just get yourself the layout diagram for the AB763 Deluxe Reverb:
 
http://www.ampwares.com/ffg/schem/deluxe_reverb_ab763_layout.gif
 
Then simply compare it to your existing amp layout and make
changes as necessary.
 
Major things in the blackface mod are:
 
1. Removal of the supression caps from the power tubes. (big tonal
difference).
 
2. Removal of the cap across the Phase inverter tube. (small tonal
difference)
 
3. Removal of the ground suppression cap from the reverb output.
(big difference to reverb tone)
 
4. Change/addition of bias caps and bias pot on left side of the
board (as you look at the layout diagram). (allows for more
accurate biasing which can greatly affect tone)
 
5. Ensure the cap coming off of pin #2 on the Phase inverter tube is
actually a .001 . (tightens up bass response).
 
6. Removal of the hum balance control (if it has one). (usually not
necessary after blackfacing).
 
7. If it's a 77 or later, you may want to ditch the pull boost volume
control for a normal 1M Audio 2-35 taper pot. (the gain from the
pull boost is a buzzy mess that most people don't like anyway...)
 
8. And while you're in there, if the amp has chocolate drop or blue
blob tone caps, recap it with either Sprague Orange Drop 715P's
(or Mallory 150's if you like a more vintage tone). (this will get rid
of stray hum and ensure the amp is gig-ready)
 
Did I miss anything guys ?
-------
Just that I like the boost on late-70s Deluxe Reverbs and
Princetons. It sounds like the Sex Pistols guitar tone, especially on
the Deluxe. I could be the only one, but if you like the Pistols . . .
 
You also missed that the reverb circuit may be a lot different, but
some amp freaks find the silverface reverb to be more lush than the
blackface reverb. I personally haven't heard much difference in
reverb from circuit to circuit, but something else seems to make a
big difference between amps with the same reverb circuit - maybe
the tranny.
 
Shea