Hey. If you want a way to thicken, or boost, the midrange, here is
a cool little circuit. Step by step instructions:
 
Parts needed: 10K midrange control with a push-pull switch, 1 meg
1/2 watt resistor, and a .002uF cap
 
1) Locate the treble cap in the preamp channel you're wanting to
install this in. In most Fenders, it is almost always 250pF.
 
2) Solder a wire coming off of each side of this cap.
 
3) On the push-pull switch on the 10K pot itself, solder one end of
the .002uF cap onto one of the switches terminals. Solder one of
these wires(doesn't matter which one) onto the other end of the
.002uF cap.
4) Take the 1 meg resistor and solder it across the switch. Since
one side of the .002uF cap is on one of the switches terminals, one
end of this resistor should be soldered to the cap also.
5) Take the other wire and solder it to the side of the switch that
has just one of the leads from the 1 meg resistor, NOT THE END
WITH THE RESISTOR AND THE .002uF CAP!
6) Plug in and rock and roll!
 
What this mod does is increase the value of the treble cap in the
tone stack by being in parallel with the 250pF cap when the switch
is closed(on), thereby giving it more midrange. The switch also
shorts out the 1 meg resistor so that the amp never sees it. When
you open the switch(off), you put the cap in series with the 1 meg
resistor again. The high resistance of the resistor returns the amp
back to the stock sound, and it also eliminates any popping noises
when the cap is switched in.
I have installed this mod in every amp I own, and have had
excellent results with it. Hope you like it!
Jonny