The Ibanez S770PB Rewire revisited

I confess: I can’t leave well enough alone

You may find the featured additional helper tools pictured here useful to you.

Recap

Previously as part of a refurbishment exercise, I managed to figure out the issue with the wiring of my newly acquired instrument.

So, it still works, but the original inspiration for the coil tap modification was targeted at a standard (non-import) Strat backplate.

I had to fix a connection I had dinged in other work, revealing a weak solder joint. I even found the diagram even with my *ahem* “helpful alterations” a bit hard to follow.

So here is an article with a more detailed explanation, run through on the wiring and diagrams that *actually match* what I have done in the guitar.

But, first some terms clarified.

“Import” selectors demystified

These are functionally identical to the original double sided selector, but need a little mental gymnastics to be lined up with a diagram drawn for the original switch.

Both switches have 3 taps fed into off a pair of electrically isolated wiper arms. For these arms, three positions simply line up the common with that tap, connecting pickup [1, 2, 3] to the output in an entirely standard approach for a mechanical switch.

Since its allegedly fortuitous discovery in the time of the dawn of tone, there have also been 2 more positions, between the positions 1,2 and 2,3 that connect the adjacent taps to allow both to connect to the output at once. This has resulted in the famous in between position sounds that have been well used by some famous exponents Clapton, Knopfler, Gilmour, Gilbert.

For the most naive/logical wiring setup “wire the pickup to a tap in the same physical sequence” this will result in the pickups being connected in parallel to the output. The most obvious outcome is both pickups’ signals are superimposed, and there are some new subtle electronic effects, which we might cover in another post.

The original style switches simply line up the two styles of connector on either side of the switch assembly housing the wiper, whereas the connector here simply has the three taps in the same sequence, separated by the two common connections.

To be clear — import style switches are functionally identical a bit more modern looking. The whole assembly is rectangular, and the contacts are entirely encased, hopefully increasing dust resistance.

More practically, the contacts for the 2 efforts are arranged in a line along the top of the switch.

When the pickups only have one output wire, then this use of one half of the switch is fine.

Whereas the classic switch was open to the elements and could be figured out by observation, the import style is worth double checking.

Old style: 1, 1+2, 2, 2+3, 3, COMMON (mirrored for contacts on the opposing side)

Import; 1, 1+2, 2, 2+3, 3, COMMON, COMMON, 1, 1+2, 2, 2+3, 3

“Tone” Controls

Again there is a slight diversion that needs to be had here.

So in conclusion, I just don’t wire them up. Less chance of mishaps on stage; sounds better to me

“Coil tapping”

This is where humbucker pickups with the handy 4-conductor wire can be decomposed into their individually usable single coil-style pickups.

The aim here is to achieve a wider sound palette from the raw material of passive electronics and switch combinations.

Why this even works at all is interesting, but worthy of a different article…

Because there is a crazy amount of customisation possible.

Better Diagram

This diagram omits all the tone control nonsense that I don’t bother with and lays out clearly where the wires should go.

diagram for the traditional 5-way selector with coil tap selector switch

Which coils are tapped?

So using the time honoured “tap it with a screwdriver”.

No seriously, plug the guitar in and gently tap the coils with a screwdriver — there is always a slight tendency to act like a microphone, but the magnetic screwdriver should generate a solid clunk when an active pickup is touched.

So, I find that the coils in use in single coil mode are not the “outermost” coils — i.e. bridge coil closest to the bridge, and neck closest to the neck.

This might not be what people would want, on the theory that the pickup positioning is super important.

We will be considering pickup positioning in a future article.

How to swap the coils used for tapping

Q: how does the wiring here work the trick?

A: It shorts the unwanted coil to ground (done this way to reduce noise pickup from unconnected circuit points) The coils were in series in humbucking mode and now one coil has ground on both sides.

So, simply swap the pickup wire pairs — imagine stacking the coils with the red->green coil on top, but keep the wiring shape the same. Ensure that the “sense” is the same (black -> white, red -> green) as before after to ensure the middle switch position do not get an unintentional out of phase effect.

Why I won’t be bothering

If the coils are identical in electronic performance and pick up performance, then the difference in sound for a centimetre of positioning will be undetectable for most cases. We’ll be looking at that in detail soon, no doubt.