IS THERE A WAY TO GET MORE JANGLE FROM THE NORMAL channel of my Fender Pro Reverb amp? I have a 12-string Rickenbacker and would like to get that clean, jangly Vox tone, but without altering the reverb channel of my amp. —Anonymous
The tone you seek can be obtained very easily by simply replacing a short wire with a capacitor and changing the value of a capacitor on the component board. This modification will work with almost any two channel Fender amp (Twin, Super, Pro, Bandmaster, Showman, etc), and it is easily reversible should you want the stock wiring again.
This mod requires only two parts: a .01uf/400-volt capacitor and a 5uf/25-volt electrolytic capacitor. You’ll need a soldering iron and solder too, of course.
Unplug the amp and put the standby switch in the “play” mode to drain any stored electricity from the amp. Remove the four chassis screws on the top of the amp; remove the upper back panel and the cabinet strain relief on the AC cord. Unplug the speaker and remove the chassis from the cabinet. With the back of the amp facing you and looking into the chassis at the right side, you should be able to match up the components in the amp with the layout in Diagram 1. Make sure your amp is similar to the drawing before proceeding.
Notice there is a straight wire connecting the middle of the volume pot to the bright switch. You are going to replace this wire with the .01uf capacitor. Next, locate the 25uf capacitor that is going to pin 3 of the first preamp tube. You are going to replace this capacitor with the 5uf capacitor. Pay attention to the polarity of this cap. The plus (+) lead should face pin 3 of the first preamp tube, and the minus (–) lead should face the front of the amp. Double-check your work, by comparing it to Diagram 2. This is what the amp should look like now.
Put the old capacitor and the removed wire in a baggie and stash it in the bottom of the amp in case you want to put it back to stock wiring later. Reinstall the chassis, the AC cable strain relief, and the upper back panel. Plug in the speaker and you are ready to test it (make sure the speaker is plugged into the main speaker jack and not the external speaker jack). Turn on the amp, plug in your 12-string Rickenbacker, and get your Byrds on! —Gerald Weber, Kendrick Amplifiers