Trick wiring for phase sw on guitar with only 2 pots

[Steve A.]

The trick to using a phase switch on a guitar with humbuckers is to just blend in a little bit of the "other" pickup rather than having both volume pots full on. That is how Peter Green got some really tasty sounds out of his LP.

Many of cheap imported guitars are coming with just two pots so there is no blending of the two pickups. While there may be room between the two pots for a mini-toggle switch, a phase switch would sound like crap with both pickups full on. My friend Felix suggested using a 3PDT or 4PDT with fixed resistors wired to the extra set(s) of contacts to attenuate one or both of the pickups in the out-of-phase position. I took the idea one step further and will use trim pot(s) instead of fixed resistor(s), at least initially to determine the desired value(s).

The same principle could be used with a switch linking two pickups together in series or parallel.

Parts Express has 4PDT mini-toggle switches for $2.48@ w/ $6.95 flat rate s/h. (They also sell DPDT and 3PDT switches, too, but they are all On-On, no center off or On-On-On. )


4PDT Mini Toggle Switch

Steve Ahola

[Richard]

I think you could wire it with just a standard DPDT and still incorporate the trim pots. This means if you don't want to drill a hole you could use a switching pot. What do the extra poles do?

[Steve A.]

I think you could wire it with just a standard DPDT and still incorporate the trim pots. This means if you don't want to drill a hole you could use a switching pot. What do the extra poles do?

With the extra poles the trim pot(s) or fixed resistor(s) would be in the circuit only for the OOP mode.
In most cases you would probably want to remove the trim pots and use just a single pole to reduce the signal from one of the pickups. However, you could leave both trim pots in and optionally drill small holes in the control compartment cover to make it easy to adjust them later which could be handy when recording.
I'll draw up a wiring diagram showing how the trim pots or fixed resistors would be wired to bleed off some of the signal to ground.

HTH

Steve Ahola

P.S. I mentioned using the extra poles for wiring up a switch to put both of the pickups in series. The Gibson/Epiphone Blueshawk runs the signal from the two P90's through a parallel R/C network of a 100k resistor and .001uF cap to both attenuate and brighten the series linkage which is louder and thicker than a parallel linkage. I'll post whatever I come up with on that...