FF TONE CONTROL / SMALL STONE VOLUME DROP

[Ricardo Antunes]

HY FRIENDS!!!! HELP ME PLEASE!!!  
ABOUT THE FF:
HOW CAN I ADD A TONE CONTROL TO A FUZZ FACE BASIC CIRCUIT (WITH ROGER MAYER MODS)?

ABOUT THE SMALL STONE:
-THAT DPDT SWITCH WHERE GOES THE CA CAP, IS IT FOR TRUE BYPASS OR ONLY A ON/OFF SWITCH? IN THE LAST CASE, COULD I FIX ONLY THE ON POSITION AND ADD A DPDT SWITCH FOR TRUE BYPASS?

-HOW DO I SOLVE THE VOLUME DROP WHEN THE EFFECT IS ON?