Deluxe Reverb Soul Switch

The "soul" switch is simply a 5K linear pot put in

series with the negative feedback resistor. The article

suggested taking out the ext speaker jack which has 2

connections. One is the speaker signal from the main jack, the

other is the negative feedback wire going back to the circuit

board. Looking at the back of the switch, with the terminals up

call the terminals from left to right 1-2-3. Speaker connection

to 1, negative feedback to 2. 3 can be connected to 2 also for

increased reliability. At "0" the loop is stock. Turn it up the

negative feedback is taken way down and the amp will open up

with more gain, breakup, floppy low end (and noise.)

Another tech in town has this variation. When modding SF

master volume Fenders, he will take out the 10K mid control

and replace it with a 25K. Excellent move. He will then use the

10k as this "soul" control and mount it in the master volume

position.