Phase Reversal Switches In Humbucker Equipped Guitars

Discussion in 'Guitars in General' started by wildschwein, Oct 8, 2008.

  1. wildschwein

    wildschwein Member

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    This post originally began as a response in the "Why Don't You Like Humbuckers" thread but I decided it should probably be a thread unto itself.

    I recently installed phase reversal switches on two of my all-humbucker equipped guitars. This is an old mod that was pretty popular in the 70s and the early 80s which you don't see talked about much anymore; especially around here on TGP - sorry to everyone who remembers it; no disrespect is intended. I've played for 20 years and had heard of phase switches but had never actually heard what they did first hand - man I've really missed out. I've seen some people mention Jimmy Pages LP here at TGP which I guess had coil tap and phase switching; but that's about it. Search function doesn't seem to reveal too many entries.

    To anyone who doesn't know, guys like B.B. King and Peter Green used out-of-phase tones for their lead sounds, usually with a nice dose of reverb from their Fender amps to make haunting, sweet, but biting tones. Brian May also has heaps of phase options on his Red Special guitar - many of his solos are actually out-of-phase tones. Andy Summers also used to have a phase switch on his #1 Tele that let him throw the Gibby humbucker and the bridge single coil out of phase with each other too. Some of those classic Police sounds where also generated by this old mod. I also suspect that Billy Gibbons has used out-of-phase humbucker sounds on some of his solos over the years - got no proof; just sounds like it to me. Could be a Strat, I guess, but "Blue Jean Blues" comes to mind. Please feel free to list some more artists known for out-of-phase tones if you know of any.

    There are different ways of doing it - the Peter Green style involves reversing the polarity of the neck PUP by disassembling the PUP. You can install a pull-pot in your guitar as a new volume pot that has a DPDT switch built onto it which is activated when the pot is pulled (or pushed) - pretty sure this was what Jimmy Page had. I used straight DPDT switches and drilled holes in the control cavities to install the mod in my in my axes - this was the hardcore scary way to go; but it turned out well and I didn't ruin anything. Kinda freaky drilling through your guitar though - measure twice, cut once is what I kept telling myself before I committed to power tool.

    When you engage the phase switch it throws the bridge PUP out of phase with the neck PUP; if both PUPs are selected. The original sound of both humbuckers is still present though if you don't switch the phase switch on. So nothing is lost - you just gain an extra sound. It gives a completely different tone when engaged - much thinner, slightly quieter and a little hollow sounding - much more single coil in nature. It's sort of like dragging a comb filter through your sound - a lot of the bass harmonics and some of the mids are subtracted and the tone is more biting - but it's totally usable and also makes the sound of any effects you have running stand out more clearly. With a Tremolo effect and some reverb dialed in, for example, the sound is really Fenderish. It's like getting a whole new guitar sound that you can switch in and out of a humbucker axe.

    I think phase reversal switches need to come back in fashion - it's a really cool usable mod for humbucker guitars that lets you back off on some of the fat tones if you need to. I remember Clapton saying once in an interview that he switched to Strats because he couldn't back off on the fatness of LPs and SGs and FBs etc., - he should have dropped in a phase reversal switch. You can also do it on single coil equipped Teles if you have the right wiring in you PUPs too - I imagine that would give a new meaning to "twang".

    The switches only cost me $2.25 Australian each from my local electronics store - once I'd worked out what I was doing the mod only took about 30-40 minutes to perform on one guitar - you don't even need to take the strings off LP-style axes either. All the work is done in the vol/tone control cavity which makes testing easy.

    I got most of the info from here down the page a bit: http://www.1728.com/guitar.htm

    Here's some notes I put together from my own experiences performing this mod:


    You seem to need PUPs with two ground leads (or two hot leads) - usually PUPs which have 4 wrapped and coloured leads and an unwrapped core have this - the unwrapped core wire is the ground, 1 is the hot lead, 1 is another ground or hot lead, the other 2 leads are usually for coil tap options and will often be soldered together; if the guitar doesn't have coil tap options available. In the already set-up guitar you should see the uncovered ground wire and another covered wire (usually black on a lot of PUP brands) that are both soldered to the back of the volume pot. For the mod, one ground lead - the unwrapped core wire still goes to the back of the volume pot and the other wrapped "ground," probably the black one, goes to one side of the DPDT switch as described in the link above. If you just reverse the ground and the hot leads on an old-style, two lead-style humbucker PUP you get a lot of noise and hum when the PUPs are thrown out of phase - because one of the PUPs will no longer be grounded - so only try it if you have all the wire options available. Also check your PUP brand on the web through Google etc., to try and discern what the lead colours represent. My PUPs are GFS units but I know Seymour Duncan has a great wiring page where there are diagrams of nearly every conceivable PUP configuration. See: http://www.seymourduncan.com/support/wiring-diagrams/
     
    Last edited: Dec 21, 2009
  2. OlAndrew

    OlAndrew Member

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    Ted Greene used to do this kind of thing. I remember playing with some of his guitars with lots of little switches on them.
     
  3. kimock

    kimock Member

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    I'm a big fan of the phase reverse switch on the standard two volume, two tone, two humbucker guitar.
    If you select both pickups, flip phase, and turn the tone control off on one pickup, you can get some really nice "wah" type effects in the higher registers as you bend the strings.
    When the string is not bent, and it's passing directly over both sets of pickups polepieces you get the "out of phase" cancellation thing, but when you bend the string, it moves away from top dead center on the neck pickup polepieces enough to get a radically different timbre as the "out of phase" sound shifts to the straight back pickup tone.

    I think that's the cool part of the out of phase thing for me, the way you can go in and out of "out of phase" by moving the relative amount of cancellation around with your vibrato and bending.
    It's not at all a static effect.

    peace
     
  4. wildschwein

    wildschwein Member

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    Thanks for posting that; it sounds like it would be really cool - I'm gonna go and give that a try.
     
    Last edited: Oct 9, 2008
  5. straightblues

    straightblues Member

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    I have it on all of my humbucker guitars. I really like how it sounds. You can adjust the volume of each pickup to fatten things up.

    Here is a wiring diagram on how to do it with a push pull pot.

    http://www.seymourduncan.com/support/wiring-diagrams/schematics.php?schematic=phase_switching_for_hb

    Here is the Peter Green mod:

    http://www.stewmac.com/tradesecrets...m_medium=email&utm_campaign=ts0069&clk=195805

    Here is you tube video that explains how it sounds.

    http://www.youtube.com/watch?v=F6qkF_6LNPA
     
  6. 908SSP

    908SSP Supporting Member

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    I put one on a Strat type guitar with three single coils, just the center pickup throw it out of phase for very different 3 and 5 position tones.
     
  7. cob666

    cob666 Member

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    I had a Les Paul classic that i installed mini toggles under the pick guard with the ends just barely visible. This way, I didn't have to put push pull pots in and there was no drilling required. Although the luthier (Jim Mauradian in Cambridge, MA) did have to modify the pickup rings a but to get the wires through. It was very slick, all i had to do was slide a finger across the bottom of the pickguard and I could put one or both pickups out of phase.
     

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