Originally Posted by ajish4
"The pickups are wired in series with the white and black being the endpoints. The red wire is the centertap wire that's tied in between the two coils. The bare wire is the ground of the chrome cover to be soldered to the case of its volume pot. We really needed a 350k ohm pot as the red wire allows a bit of bleed-off of high overtones. I highly suggest clipping or disconnecting the red wire at the tone pot. You will have a more full sound, as you'll be using those high overtones at full treble position of the tone knob.
I'm resurrecting this thread in the hopes that someone may be able to help me think through the above mod to the T-40 pickup circuit.
According to Hartley Peavey in this
article (see pages 13-15), the T-40's single coil/humbucking switching feature works by using the tone/mode potentiometers to ground the center tap (red wire) coming off of each dual-coil humbucking pickup. This has the effect of taking one coil out of the circuit, leaving only the other coil sending a signal to the output jack.
As the tone control is turned down (counter-clockwise), resistance increases, and the center tap is "ungrounded," which allows both coils back into the circuit.
So far, so good. Here's where I'm getting lost: as far as I can tell, if you cut the red wire leading to the tone pot, the coil tap never gets grounded, which means that the pickup will not be able to function in single-coil mode. True, you'll keep extra high overtones, but you'll always be in humbucking mode.
Or am I missing something...?
Here's a copy of the T-40 wiring diagram, for reference: