Fresh_Start
New member
About six months ago, my oldest friend called from Maine and told me that he'd borrowed some old Fender amp from a neighbor. "A something-or-other reverb amp" he said. "Deluxe Reverb or Princeton Reverb? What color is the control plate?" I asked anxiously. "Uh, Princeton I guess. What's the 'control plate'?" Turns out his (insane) neighbor loaned him a Blackface Princeton Reverb just to noodle on!
John's a great guy, but he's only been playing guitar for a couple of years and hasn't gone gear crazy like some of us
Sure likes that amp though.
To make a long story a bit shorter, I had recently bought a set of Mercury Magnetics transformers for a Princeton Reverb build because I got a chance to buy them at the +25 unit price but had planned another build before tackling a push-pull amp with reverb and tremelo. John loved the vintage P.R. but kept getting shocked by it every once in a while (2-prong cord and vintage "death cap" still in place - ugh!). So I agreed to build him a Princeton Reverb clone and here are some slideshows of the build:
Circuit Board
Chassis Prep
Completed Amp Gut-Shots
I finally tracked down a bug today (bad tone stack cap) and got everything working great except for fairly lame reverb. The cab is from Mojo - really nice build in pine, box joints, floating plywood baffle. Weber 10F150T speaker. Mallory coupling caps throughout. Mecury Magnetics iron.
The circuit is almost pure vintage with the following changes:
1) addition of bias adjustment pot
2) added 470 ohm screen resistors
3) added 1K5 grid stoppers on the 6V6s
4) added 1 ohm 1% bias check resistors on the cathodes of the 6V6s
5) increased first filter cap from 20uf to 40uf and put two 20uf caps in parallel for the screen supply instead of just one (JJ cap can at 40-20-20-20)
6) changed to 22uf 50 volts bypass cathode bypass caps on the preamp stages (instead of 25uf 25 volt)
7) increased 47uf 100v filter cap for bias supply (was 25uf 50 volt)
8) added standby switch
9) optional master volume pot (cross-line post phase inverter type)
10) optional 470 ohm "safety resistor" on the speaker jack
The layout is very close to one developed by the fantastic guys over on the Hoffman Amps forum - many thanks to everybody there who's helped me!
A really cool aspect of this project is that I bought the parts for two builds at the same time. The second build will be for me to keep. I plan on adding a "Mid" control and "Dwell" for the reverb, plus a few other tweaks.
Anyway, thought I'd share this project with you all. It is wonderful to be able to plug a guitar in and play through the amp after all of the research, finding & buying parts, planning and revising the layout, and carefully putting everything together
Cheers,
Chip
John's a great guy, but he's only been playing guitar for a couple of years and hasn't gone gear crazy like some of us
Sure likes that amp though.To make a long story a bit shorter, I had recently bought a set of Mercury Magnetics transformers for a Princeton Reverb build because I got a chance to buy them at the +25 unit price but had planned another build before tackling a push-pull amp with reverb and tremelo. John loved the vintage P.R. but kept getting shocked by it every once in a while (2-prong cord and vintage "death cap" still in place - ugh!). So I agreed to build him a Princeton Reverb clone and here are some slideshows of the build:
Circuit Board
Chassis Prep
Completed Amp Gut-Shots
I finally tracked down a bug today (bad tone stack cap) and got everything working great except for fairly lame reverb. The cab is from Mojo - really nice build in pine, box joints, floating plywood baffle. Weber 10F150T speaker. Mallory coupling caps throughout. Mecury Magnetics iron.
The circuit is almost pure vintage with the following changes:
1) addition of bias adjustment pot
2) added 470 ohm screen resistors
3) added 1K5 grid stoppers on the 6V6s
4) added 1 ohm 1% bias check resistors on the cathodes of the 6V6s
5) increased first filter cap from 20uf to 40uf and put two 20uf caps in parallel for the screen supply instead of just one (JJ cap can at 40-20-20-20)
6) changed to 22uf 50 volts bypass cathode bypass caps on the preamp stages (instead of 25uf 25 volt)
7) increased 47uf 100v filter cap for bias supply (was 25uf 50 volt)
8) added standby switch
9) optional master volume pot (cross-line post phase inverter type)
10) optional 470 ohm "safety resistor" on the speaker jack
The layout is very close to one developed by the fantastic guys over on the Hoffman Amps forum - many thanks to everybody there who's helped me!
A really cool aspect of this project is that I bought the parts for two builds at the same time. The second build will be for me to keep. I plan on adding a "Mid" control and "Dwell" for the reverb, plus a few other tweaks.
Anyway, thought I'd share this project with you all. It is wonderful to be able to plug a guitar in and play through the amp after all of the research, finding & buying parts, planning and revising the layout, and carefully putting everything together
Cheers,
Chip
