Duane Eddy's House of Twang

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Sorry about posting this twice, but I got no answers. I want to add a phase reversal switch to my 5120 to put two P90s out of phase with each other. I saw on this site a diagram for the switch, but I'm not sure where to solder the grounds and leads. What gets soldered to the + & - inputs and outputs of the switch and how does this all fit into the wiring harness. What arrangements must be made to make this work? The pickups have a single lead and a braided ground wire.


You basically need to reverse the phase of either pickup...so it doesn't matter WHICH pickup's leads you connect the switch to...as long as you reverse the phase of one of the two pickups...when you throw the switch the two pickups will be out of phase combined. I would do this switch business BEFORE the pickup wires hit the volume pot. To avoid drilling holes you MIGHT want to consider a push/pull pot as your "switch"

So basically the two wires coming off the pickup go in as + and negative at the top, and come out the middle "switched"

After the switch just connect the wires coming off the center lugs of the switch to where they would go normally on the volume pot.

One other tip: Do NOT combine the ground wire with either pickup wire....just ground it independently..that way the pickup case will always be grounded regardless of which direction the switch is.


Here's an example of a two volume, one tone setup that has phase reversal (forget about the label saying "humbuckers"...just think of this as two P-90's). The bridge pickup hits a volume pot and then goes to the 3 way switch to combine with the other pickup in the normal way. The NECK pickup's wires hit the push pul pots lugs first and this allows THAT pickup to reverse the two wires...after which it hits the volume pot and then the two pickups combine at the 3 way switch. The tone does it's thing as a master tone to the combined signal AFTER the 3 way switch. I think your guitar has a "master volume" (separate from the 3 controls) that you can add here after the switch to the combined signal before it hits the jack. Personally I hate master volumes on guitars...they make things muddy in my opinion....I'd just disconnect it and do the wiring as shown.

Note that the bare wire off the neck pickup isn't combined with either wire and grounded separately


2 volume, 2 tone with phase reverse. forget about "pull for single coils" P-90's are ALWAYS single coils.


My pickups are single conductor with a braided ground. Do both pickups need their leads attached to the DPDT switch on the pot? How can I do this so I can keep the master volume?


With two single coil pickups, all you need to do is wire one pickup for phase reversal. It's only going to sound different when the pickup selector is in the middle position anyway (both pickups activated).

And be sure to ground the switch casing.


>>>My pickups are single conductor with a braided ground.


Not to butt in here but:

1 . The phase switch goes on one PU only as mentioned.

2 . The phase switch is installed as the first thing the PU output sees. So it can easily be installed before the individual PU volume. This all has no effect on your master volume operation.

You can install the phase switch after the individual volume if you want. In principle, there is some arguable noise benefit to installing it before the individual volume. In practice it often makes no difference.


Right now you describe having a single conductor wire with a shield/ground coming from the PU. When you reverse the phase on this PU, the shield (and PU plate) will become the hot conductor from the PU and you can expect noticeably more noise under some conditions. Also, this now-exposed hot signal line can accidentally touch a grounded surface inside the guitar, which is a pain.

The solution is a bit beyond just re-wiring the PU to a phase switch. It is best to replace the PU lead with a 3 conductor lead. That is a wire with two "hot" conductors plus a shield.

The hot conductors go to each end of the PU coil and the shield goes to ground both at the PU (metal plate) and in the guitar circuitry.

If you feel up to this slightly exciting job, I can send you a lead wire (or you can buy it from the usual suspects).

But this does involve taking the PU apart.

Many guys ignore all of this and accept the extra noise that can come by using the shield of the PU lead as the hot signal line.

Getting off-track now:

When doing a 2 X P-90 install, I like to set them up as humbucking in the middle position. This is done by reversing the magnet and the coil directions on one PU. This makes the PU's humbucking when used together and "in-phase". It is a small trick that is sometimes helpful. This is not at all necessary.


I want to get a GFS Dream 90 for the bridge instead of the Phat Cat I was referring to. A member here said the Dream 90 has (if he recalls) "two wires with a braided shield that you can connect with one of the leads to ground (you get to select the phasing)" So could I have the push/pull DPDT pot be the bridge volume pot instead of the neck? I assume I could, but you guys are smarter than me. Also has anyone had experience with the Dream 90? Are they really 2 conductor with a braided shield?

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