From: till@acid-rain.lucid.com (Don Tillman)
Subject: Re: humbucker theory (was Ibanez hum)
Reply-To: till@lucid.com
Organization: Lucid, Inc.
Date: 4 Oct 92 22:07:33

   Date: Sun, 4 Oct 1992 22:42:56 GMT
   From: META000 <META@UNB.CA>
   Organization: The University of New Brunswick

   As usual, Don and R.G. set me straight.  (Maybe it's true. Maybe you
   DO need an engineering degree to be a musician these days!)

Heh-heh; one could argue that this discussion has darned little to do with
music.  

   Don mentions the phenomenon whereby pickups attain their
   characteristic sound by virtue of variations in the magnetic
   relationship between string and polepiece, and how the amount of
   string length within the "eye" of the pickup determines timbre.  I
   assume that when the wave length of a note is such that "upsy" and
   "downsy" parts of that wave are each within the "eye" of the pickup
   (or both "eyes" in the case of humbuckers), then the two components
   cancel each other, leaving only those string vibrations that are
   uniquely represented at the pickup.  Peaks and troughs of high
   frequencies are so close together that they are usually somewhere
   within 180 degrees out of phase over each polepiece, giving the
   meaty, but lustreless, sound of a humbucker.

Yep.

   I understand why the dimensions of the humbucker have become a standard
   of sorts these days, given how desirable it is to be able to buy a
   pickup and just pop it in.  Standards for cavities need not imply
   standards for coil-spacing and voicing, though.  It seems to me
   that given how capable we've become at making eensy weensy
   coils that can fit two to a single-coil-case, its surprising that
   someone hasn't tinkered with an adjustable voicing pickup to fit in
   a standard size humbucker chassis.  

Bartolini pickups come in all sorts of variations built with the humbucker
form factor: single coil, split humbucker, dummy coil, vertical hum
canceller, tapped coils, and triple coil.  Oh, and regular humbucker.  Plus
coil tap options.  And no goofy names like "humbucker from hell" or "ultra
vomit death".  Though I've never played them, word on the street is that
they're very nice.  Tuck Andress has one on his old Gibson L-5.

There's also the Gibson Firebird pickups which, though not technically a
humbucker form factor, come close, and are sort of a mutant vertical
humbucker on it's side.  Real clever.
				       
				       Technically, itought to be
   possible to make two small coils,one of which could slide backwards
   and forwards inside the chassis, resulting in the cancellation of
   different frequency components.  

The magnetic field on a humbucker isn't exactly like two single coils; but
no matter, this is certainly an interesting idea.

   Another idea I had for a pickup, and just never got around to
   making, was a "coil-swapping" pickup that utilizes 3-coils, two of
   which may be swapped to produce either a side-by-side humbucker or a
   stacked humbucker.

Interesting idea.  I've never heard of anybody doing it before.

   Wind a standard single coil Fender-style pickup, but tap it after
   half the turns.  Since many of the turns would be at both magnetic
   poles (i.e., the north and south ends of the polepieces), this
   tapped coil, in tandemwith the extra coil on the front of the pickup
   (where all the turns would be primarily at one magnetic end) should
   constitute a reasonably, but not perfectly hum-rejecting pickup.
   When the extra coil is deleted and replaced with the remainder of the
   windings on the main coil, we should get a standard single coil
   sound, hum and all.

I don't think this will work, but I'll admit to not understanding this
description real well.

   Now, if someone could only explain to me how Lace pickups reject
   hum.

"Radiant Field Barriers", man.  (Facetious reference to Fender's lunatic
marketing.)  Lace pickups don't reject hum in the sense that they're
noiseless or cancel hum or anything; they're just much less sensitive to
hum because they have these metal (steel?) side and bottom dealies
shielding out a large portion of the noise.

  -- Don