Multiple Sounds from Humbuckers


ACT stands for Asymmetric Coil Tap. A coil of wire can be tapped at any point, regardless of whether the coil is around one or two spools. A coil tap can be used for a hot connection or for an earth connection. Asymmetric coil taps are any coil taps that are not at the centre.

ZeFront1In a humbucker, we are all used to  having 4 conductors, at the start and end of each spool. This is the easiest way to wire humbuckers bt not necessarily the best. The two spools are normally then connected at the finishes or the starts of the two spools. The 4 conductor system allows the user to decide which and so change the phasing if required. It also provides the possibility to connect the two spools out of phase.

Most often the extra wires are used as simple coil taps, splitting off one of the coils. This tends to produce a thin, weak tone especially for vintage humbuckers.  This should not be surprising, considering that a typical strat single coil has an impedance of around 6k ohms compared to a typical split vintage humbucker having an impedance of around 3.75k ohms.

In addition, a strat single coil pickup has a tall narrow winding and a strong narrow magnetic field.  A humbucker has short fat windings and a weak wide magnetic field.

Gemini pickups do not provide any opportunity to  connect the two spools out of phase as they are connected (in series) internally.  The coil tap(s) provided are located within one or both of the spools.

This means that the "single coil" sounds and alternate humbucking sounds use parts of each spool. Consequently, all of the tones have some of the effects of combining two spools.  In the main, these are increased harmonic richness, particularly in the mids and bass.  The degree of this varies with the proportions of the two coils used.

Using all of one coil and 10% of the second coil produces a very different tone from using 55% of each coil. these differences allow the design of "single coil" sounds in a wide range from strat like tones to Hot P-90 tones.

BLFront1Given the differences in design of the various types of single coil pickup, it should be no surprise that the bigger "single coil" tones produced by ACT are much closer to their real single coil equivalents than the smaller ones.

The intention of ACT is not, however, to produce authentic copies of any other pickup's tone. The intention is to produce tones that guitarists can and do use.

I certainly have rarely used the split tones of humbuckers but I do use the tapped tones of my own pickups. I hope, and I believe that other guitarists will do the same.

Copyright Mike Rose 2006 -2015. All trademarks acknowledged.
Stratocaster, Strat, Telecaster, Tele, Jazz Bass, Precision Bass are trademarks of Fender Musical instruments corporation.
Les Paul, LP, P-90, Burstbucker, "modern classic", Firebird are trademarks of  Gibson inc.
Epiphone, Wildkat, Casino and Sorrento are trademarks of the Epiphone Company.
RIC, Rickenbacker are trademanrks of Rickenbacker International Corporation.
Gemini Pickups is not affiliated with any of these companies and the above terms are used for descriptive purposes only.

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