Fender AB763-style Valve Guitar Pre-amp Custom Build

We were asked to make a valve pre-amp for a customer who wanted a simple clean Fender-style pre-amp, mainly for playing jazz.

Here are some of the parts before the build.

 

JPFVP1

 

The PCB is a charge pump circuit from Tube Town that boosts the incoming voltage (12VDC in this case) to a user-adjustable 90-220 VDC. The idea was to power the pedal from an easy to source 12VDC supply; you can wire a 12AX7/ECC83 heater to run on 12V, and the HT can be supplied by the charge pump so that the valves are running at a decent voltage. By the way can you spot the mistake?

Here is the final assembled unit:

JPFVP2

 

The circuit is the Blackface Fender AB763 circuit. I added a master volume to control the overall level of the output, and final output is buffered with a high-voltage MOSFET source follower for low impedance output.

The circuit was hand-wired using PTFE eyelet board. Sorry that there are no snaps of the inside but the customer wanted to use it at a session so I didn’t have much time with the final unit.

 

 

This entry was posted in Amp building, Effects pedal, Guitar Amps, JPF Amps, Pedal building. Bookmark the permalink. Post a comment or leave a trackback: Trackback URL.

Leave a Reply

%d bloggers like this: