Pickup Mutilation

[Rick Hardslab]

I'm working on a Westone Spectrum series bass.  It has a Precision Bass pickup configuration and one of the pickups is fried.  The pickups are two single coils, but only half of each pickup has the pole pieces and magnets on it.  The pickups have winding around the whole thing, but half of it is vacant in the middle.  Would it be possible to pull the pole pieces and magnets off of the fried pickup and put them in the empty slots on the functioning pickup and expect it to work as a normal single coil, rather than the stacked design the manufacturer intended.

[Mark Hammer]

If you go to the pickup makers forum at Ampage, you'll find lots of stuff on it in previous threads, but the quick and dirty story is that pickups act as both sensors and antenna.  The coil picks up EM/RF signals as an antenna would, including hum from transformers, flourescent light fixtures, TVs, etc.  By virtue of having a magnet in the middle, the coil also senses the disturbances in the magnetic field created by having magnetically attractable things moving around nearit....like strings.

Humbucker pickups reject hum by taking two reverse-wound, reverse polarity coils and combining their signals.  The hum that the two coils pick up, as "antennae", largely cancels out when the two antiphase hum signals are combined.

The use of two coils with magnets, however, produces a "thicker" tone by virtue of having a wider sensing area.  This can be great for guitar but make for muddy tone in a bass (or at least muddier tone than the designer is aiming for).  By removing/omitting the magnetic core from one of the coils in a dual pair, it continues to act as an antennae but will not detect the string via the second "dummy" coil.  This has been used many times in the history of electric guitar to produce nominally "single-coil" tone, while getting hum-rejection at the same time.  The famed Alembic basses, produced with support from the Grateful Dead in the early 70's, had a dummy coil in the middle, plus a neck and bridge pickup.

By moving the magnets to the "other" coil, in your particular circumstance, you may well be able to resurrect the pickup, assuming you can easily insert them without tearing the second coil.  Of course, since one of the coils appears to be damaged already, you will not get the hum-rejection you did originally when both coils were functioning.

If you are up to it [and especially if you don't: a) drink a case of cola or coffee every day, b) smoke a lot, or c) have parkinsonism ], rewinding the damaged pickup isn't all that hard.  You can buy small spools of magnet wire for winding pickups from Stewart-MacDonald.  While I wouldn't recommend hand-winding, it is not unreasonable to rewind a single coil by hand.  Keep your hands clean so things don't snag and break, and set aside an hour.

Alternatively, sometimes you can locate a free end on the coil by gently rubbing a soft eraser over the coil.  If you're lucky, you may be able to locate a solderable end and restore electrical continuity to the nonfunctional coil.

[Rick Hardslab]

I figured I'd offer an update.  Perhaps I wasn't clear enough before.  The pickups were two independent single coils that fit together.  So I took the pole pieces and magnets off one pickup chassis and just stuck them on the empty spots of the one that was functioning.  The procedure did not work as well as I could have hoped.  Even though the winding includes all the pole pieces the balance is not right.  But I put the pickup on its side with the pole pieces facing the bridge and the balance evened out.  I don't know if it is reacting with the ground plate it's laying on or what, but the bass doesn't sound too bad.  This is obviously not standard procedure, but it worked for my purposes.