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Article from Electronics & Music Maker, October 1981 |
Three different sounds from one pick-up.
You may remember a while ago Ibanez produced a guitar featuring 'Tri-Sound', and Elektra produced a guitar with a similar switching capability — though how widely the latter got round the UK I'm not sure, I saw a sample. Both guitars utilised humbuckers, and provided switchable normal humbucker/single/in-phase coils for one or both pick-ups. The switch that I saw on the Ibanez was one which I use quite extensively, an FTPA41, made by the New Ohto Co. Ltd, yet another bunch of cunning Orientals. The 4 in the number refers to the toggle shape, in this instance a triangulated paddle. The F refers to the series, a quite inspired range if you're a switch freak like me, and the rest denotes an on/on/on DPDT (yes, double-throw, the centre on is incomplete — more later) similar to the JBT on/on/on, used in the Elektra.
You may have a little trouble getting hold of this item. JBT used to be run in the Schecter catalogue but have now been superceded — I imagine there must be an equivalent but at the time of writing don't know it.*
*Maplin's sub-miniature toggle L (FF72P) can be used for this circuit, and matches the switches currently supplied with DiMarzio pick-ups. The same three-way switching is a feature of the Shergold Masquerader guitar.
The FTPA41 may be available via Ibanez dealers and I believe there may also be a similar function Alco. Personally, I have only used a couple of Alco on/on DPDTs, and I broke both of them. I've used quite a few JBTs and FTPA41S for quite a while, and had no problems so far. If you do have trouble getting hold of a suitable switch, get in touch with me, I may be able to help. The switch must make contacts as shown by the dotted lines in Figure 1. Note that the diagonal opposites in the centre position may be either way round, and they should be checked with a simple circuit tester before wiring up. It doesn't actually matter at all which way round they are for the purposes of normal/single/in phase switching, but this switch has applications for series/single/parallel coils, as a stereo selector switch, for power off/stand-by/power on switching and more.
Wiring is as in Figure 2 for the 'Tri-Sound' type of wiring, and while I fully appreciate Ibanez's interest in the matter, it is not unique and I make no apology for using DiMarzio colour coding as it is the most commonly known up and down the country.
You can see fairly clearly from Figure 2 what is happening. In the toggle down position, that is, centre terminals in contact with top terminals, signal is taken from the red conductor of coil 1, and black and white are linked to give the normal out-of-phase series coils of the hum-bucker. In the toggle up position, that is, centre contacts linking with lower terminals, the phase of coil 1 will be reversed to normal, and signal will now be taken from coil 1 black via the diagonal link wire, and red will now link with white to give coils in series but in-phase. In the toggle centre position, whichever way the diagonally opposite contacts are made, there will be an incomplete circuit on coil 1, and signal will be taken zig-zag fashion from white and coil 2 only. Pick-up mounting is the only way of deciding which coil to tap off in relation to other pick-ups. Overall phase reverse on top of this is perfectly feasible, would operate on all settings, and would be achieved simply by running the output from the switch and the green to a normal diagonally wired on/on phase DPDT as in Figure 3.
Well, it's an interesting wiring; so it's a pity that on its own, a pick-up with coils in phase sounds terrible, hums excessively, and has a hefty relative power drop. But does your average golf club secretary or Admiral swig away at just angostura? No, he sloshes gin and tonic all over it first, and this is exactly what this wiring is, a mixer. It mixes best of all when used on a neck end pick-up in conjunction with a tapped centre pick-up, and in spite of possible heavy-ish connotations, is very much a picker's mix. Get the overall phase right (on my guitar, pick-ups out) and it will give a brittle sweetness that emerges from the hurly-burly of a band mix with Dobro stamped all over it. Back it off via a treble bypass capacitor and strum it, and you have the apparent equivalent of the top end of a well recorded acoustic rhythm, or the piece de resistance, open tune it, shove it through a chorus, and chord harmonics played rasgueado will give a very convincing auto-harp sound. It positively reeks of greenery and Mother Maybelle (begging her pardon) and used properly, gives the sort of feel that you will not get out of a guitar synth in a month of Sundays.
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Feature by Adrian Legg
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