Questions about tele "4-way" switching

[Stephen Landry]

I recently found some info on people modding their teles from a 3-way to a 4-way switch, giving them both pickups in series and parallel.

The first thing I wanted to know is how do the two sounds differ? What's so special about the new fourth position?

And second, I play a Melancon P90 Artist loaded with Fralin P90's. I have a three way switch and an unused 3-way mini toggle. Can I get a 2-way mini-toggle and wire it up to switch between series and parallel when the main 3-way switch is in the middle? I assume this will work with P90's as well as single coils?

Thanks in advance for any help!

[Pedro58]

I have 4-ways in both of my Teles, and I love it. The series combo sound a little like a neck humbucker. Round and fat with a little chirp. The output is slightly higher than the other positions, but not so much as to be unusable.
I have no idea what p90's would do. Your combined series sound would probably be very hot. I'm guessing it would be very cool, though. As to how to wire it with a mini-toggle... I would have to monkey with it. I can show you the diagram for the 4-way. Perhaps you can figure it out from there? Hope this helps!

[Jim Collins]

You will probably have to modify one of your P90 pickups to accommodate series operation. P90 pickups are usually built with a single conductor and a braided shield. The shield serves two purposes -- the ground for the coil, and the ground for the metal base of the pickup. The metal base must always be grounded, but in series operation, the ground of the coil will be connected to the hot lead of the other pickup. In order to accomplish this, one of the pickups must have seperate grounds for the coil and the base. Typically, P90s aren't built this way, though yours might be. The mod isn't particularly difficult, but it is a necessary requirement.

[Stephen Landry]

Thanks for the info guys!

Jim, the mod needed to the P90's for this, will it effect the tone of the pickups at all, or is it just a technical thing?

Thanks again!

[Jim Collins]

It is possible that there might be a slight change in tone. There is a certain amount of capacitance associated with the braided shield, when it is also used as the ground for the coil. This acts as a tone control, bleeding a small amount of highs to ground. By making this mod, you cause the braid to be used as a ground for the base, only. I don't really know how much of a change there would be, or whether you or I would even recognize the difference. Even if there were a difference, you could compensate for it with the tone control.