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.
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.
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
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.
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.
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.
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
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
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
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.