List of tasteful modifications that I'm implementing that allows me to maintain an honest '65 vibrato channel circuit, but with additional tricks. I learned a lot of these tricks from comments on my YouTube channel as well as from Rob Robinette's website.
NOR channel tone stack will be a Fender Custom Shop Dual Professional stack
Polyester Orange Drop capacitors - (Original '65 used polyester, the DRRI uses polypropylene blahh)
Metal film resistors anywhere that's going to ground as well as RN70 plate load resistors
Mogami coax internal wiring for sensitive signal areas
Silver Mica caps replace all-ceramic caps
Move the power supply from the dog house to inside the amplifier
NOR channel added reverb
Wirewound power supply resistors for the lowest thermal noise floor
VIB/NOR channel with push/pull volume pots for bright cap
Mid pots added in place of Input 2 on both channels
Alembic style preamp out so I can run the preamp into another power amp (like my SSS) 😎 Jerry Garcia style mod
Vibrato disconnect switch like SRV's Vibroverb 50KRA with switch https://www.tedweber.com/wp503ras
Do It Yourself Layout Creator (DIYLC) layout and all of my files for this project located on my GitHub https://github.com/colganr/fender-deluxe-reverb
YouTube Playlist https://www.youtube.com/playlist?list=PL7cXUZ8g7NhSbACVai7X8FXtYO0IpqZlp
As-built layout
Looking to pull board and hand wire red knob era Dual Showman. Hoping to preserve the sonic clarity of chan 1 and make chan 2 more meaty and tasty. I play in a Garcia style, so I like the high headroom, but he also crunched pretty hard, not just in his Mesa year(s), Marshall? The Showman is without reverb, and thats ok. This mod looks great and esp w the Mayer tone on chan 2. I'm leaning toward pulling the board, I'm afraid to loose to clarity of ch. 1 on the red knob. Not sure what difference this AB763 circuit has with the 65-8 Dual Showman, nor do I know for sure if back then its ch.1 was known for its clarity? I'm running a JBL E120 and an Eminence Commonwealth, usually just the E120. Are there essentially two separate pre-amps on your circuit? Basically I'm trying to improve the sound on ch. 2 in a Jerry informed way. Not so much a John Mayer /SRV Dumble way. Jerry, sounding like 1980 Keen College, After Midnight->
Thank you for any input, and thank you for sharing your great work.
I love what you’ve done with the AB763. I’m working on a similar project based on hoffman 6L6 single channel plans but I’m incorporating some of your changes. I’m most interested in the preamp output you’ve stuck in here. Is that switchcraft jack much different than 12A? it seems the ring conductor isn’t required. I’m just not familiar. Also, as far as placement goes, that’s right in front of the phase inverter, right? Grounded when a plug is inserted?
Keep up the good work!