LEFT: On a stock, modern Strat, the dual-pickup settings (positions 2 and
4) use a parallel wiring scheme. RIGHT: When two pickups are wired in
series, the output of one pickup goes into the input of the other, increasing
volume and emphasizing low and midrange tones.
Hey fellow guitarists, it’s
time for another cool mod.
In this and next month’s column,
we’ll explore parallel/series
pickup switching schemes for the
single-coil pickups in your Strat.
We’ll begin with some theory
and then look at several cool
applications for this wiring.
As you know, like most
guitars sporting more than a
single pickup, your Strat lets
you select any pickup by itself
or choose certain dual-pickup
combinations. The standard
way to connect multiple pickups
is to wire them in parallel.
This generates the classic tone
our ears know from countless
records, when a guitarist uses
the bridge and middle or middle
and neck pickups in tandem
(positions 2 and 4 on a normal
5-way Strat switch).
Only a few guitars use series
wiring for their pickups. The
most popular examples of
series setups are the Brian May
“Red Special” and almost all
Danelectro guitars.
There are several good
reasons why you might want
to wire your Strat pickups in
series. If you want more volume
and midrange out of your pickups,
the parallel/series switching
may be the perfect option. As
I mentioned, parallel wiring
of two pickups is what you are
used to hearing from a Strat.
Parallel wiring adds transparency
and clarity to the tone.
In contrast, wiring two pickups
in series produces a longer
path with increased resistance,
adding volume while preventing
the highest frequencies from getting
through. With series wiring,
the output of one pickup goes
into the input of another pickup,
while with standard parallel
wiring, each pickup takes its
own path to the output. Besides
being noticeably louder, series
wiring emphasizes low and midrange
tones, and this is a perfect
combination to drive any tube
amp into saturation without the
help of a booster.
It’s interesting to note that
series wiring is a fairly standard
Telecaster mod, but not one
you commonly find on Strats.
Let‘s change that! It’s also worth
mentioning that neither series
nor parallel wiring has any
effect on the sound when only
one pickup is selected. The differences
occur only when two
pickups are combined.
To understand the difference
between parallel and series wiring
of two pickups, check out the
two diagrams. In the first, the
two pickups are wired in parallel,
so both pickups’ inputs and outputs
are connected together. This
is one of the main reasons why
a Strat usually has a very bright
tone—parallel wiring allows the
signal from each pickup to reach
the output jack by the shortest
possible route. The result is that
the high frequencies reach the
output jack almost unchecked,
giving your Strat that sparkling
sound we all love so much.
In the second diagram, the
two pickups are wired in series.
The theory behind series wiring
is that the ground wire of one
pickup is connected to the hot
wire of the other pickup. As a
result, they become a kind of
compound pickup, with one
ground and one hot for both.
When wired in series, the pickups
combine their impedance
(resistance) and the output is
very high. If your Strat’s middle
pickup is a reverse-wound/
reverse-polarity type (aka
RWRP), you’ll get the same
humbucking effect as you do
when the pickups are wired in
parallel—no changes there.
When two pickups are wired
in series, a good portion of the
treble frequencies is lost because
the long pickup wire works like a
resistor. Any resistor in the signal
path will suppress the signal.
The formula works like this: The
longer the wire, the higher the
resistance, and the more treble is
lost. We all know this from guitar
cables: When you use a very
long guitar cable, the sound isn’t
as detailed and transparent as it
is with a shorter cable. A long
cable acts as a resistor.
Higher frequencies are more
attenuated by a resistor than
lower frequencies, and this
explains why pickups wired in
series offer more prominent low
and midrange timbres. The signal
has to travel through twice as
much pickup wire to reach the
output jack compared to parallel
wiring—and that’s a lot of wire!
We now know why series
wiring attenuates the highs, but
why is it louder? Why do you
end up with such a beefy, meaty
tone? Let’s assume each pickup
on your Strat puts out 100 x
of power. When wiring two
pickups in parallel, each pickup
loses 3/4 of its output when
combined with the other. This
drops each pickup’s output to
25 x, instead of 100 x. Together,
you get a total of 50 x (25 x +
25 x). This power drop is why
any dual-pickup combination
on your Strat doesn’t sound as
loud as a single pickup.
But with the same two
pickups wired in series, you’ll
receive 100 x + 100 x, resulting
in a total of 200 x. Because
the two pickups are wired one
into another, the output from
the first pickup is added to the
output of the second one. This
generates a much louder tone.
However, 50 x does not
mean that the two pickups
wired in parallel are only half
as loud as a single pickup, nor
does 200 x mean that the two
pickups wired in series are twice
as loud as one pickup. Our
human hearing does not work
this way. Why that’s the case is
beyond the scope of this column,
but for our guitar-wiring
purposes, it’s enough to know
that the human ear doesn’t
operate in a linear way.
Stay tuned for the second
part of our series/parallel
discussion next month. We’ll
pick up the soldering iron and
explore some sweet parallel/
series switching options for our
Strats. This will also close out
our run of Stratocaster mod
columns. When we finish the
series/parallel discussion, we’ll
switch over to Telecaster and
Esquire mods. Until next time,
keep on modding!
Dirk Wacker lives in
Germany and is fascinated
by anything related to old
Fender guitars and amps.
He plays country, rockabilly,
and surf music in two
bands, works regularly as a
session musician for a local studio, and writes
for several guitar mags. He’s also a hardcore
guitar and amp DIY-er who runs an extensive
website—
singlecoil.com—on the subject.