Pickup Wiring

[BugWizeR]

I have a few questions on pickup wiring.

#1: Capacitor on Tone pot should go to ? I have seen various schematics, showing center of Tone Pot to
Some say ground to Tone Pot
Some say ground to Volume Pot
Some say To center of Volume Pot
Some even say middle lug of Volume Pot

#2: As in 2 Humbucker 2 Volume 2 Tone 3 way toggle, IF the 2 are seperated (no ground connecting) and the ground from each is passed thru diodes, would this keep each pickup isolated from the other in combined (middle) mode? I attached JPG, showing RED cuts, running ground from 2nd Tone pot.


#3: Does the Volume Ground (casing) HAVE to be grounded to lug 3 of Volume pot?

Any advice on these would greatly be appreciated.

 

[Artie]

Re: Pickup Wiring

#1. A tone control is a cap and variable resistor wired in series from ground to "hot". Therefore, it doesn't matter what order the cap and pot are in, or which terminals of the pot are used. (Within reason.) You still want the pot to go up and down with CW and CCW rotation respectively. Somewhere around here, I have a diagram of 8 different ways to wire a tone control that are all electrically identical. (If I can find it, I'll post it.)

#2. No. Diodes only handle DC. Your signal is AC. But even so, it still wouldn't work.

#3. No. It's done that way partially for tradition, and partially to allow the pot casing to act as a shield. Some high quality Bourns pots have plastic cases. So no, it's not absolutely necessary.
Edit: However, just to be clear, lug #3 MUST be grounded somewhere. It just doesn't need to be the pot casing.

Here's the tone pot pic. Note that all of these are electrically identical and sound the same. The bottom four are the same as the top four but with a slightly "nicer" failure mode. In other words, when the pot gets dirty, or wears out, and the wiper "lifts" off the track, the pot goes to "10" rather than open. Also, if you prep the pot by shorting those two terminals together, you don't have to worry about how the pot gets wired into the guitar. Either terminal works either way. CW is "up", and vice-versa.

 

[BugWizeR]

Re: Pickup Wiring

Thank you for the quick response. Still not sure on #1. Tone pot schem doesn't show where the capacitor jumpers to, except the ones that have it to ground.

#1: Capacitor on Tone pot (center lug) should go to ?. I have seen various schematics, showing Tone Pot center lug w/capacitor to:
Some say ground to Tone Pot
Some say ground to Volume Pot
Some say to center lug of Volume Pot

 

[Artie]

Re: Pickup Wiring

The cap and pot are in series between any "hot" point and ground. Look how I modified that diagram. Both sides are electrically the same. Often people use the cap to bridge the connection between the vol and tone pot. Then you just ground one lug on the tone pot. That's how I do it.