Pickups:: Pickup Wirings
Pickup wiring is one of those items that is worth
knowing, especially if your bass has two pickups or split type
pickups. Most pickups are wired in parallel configuration to the
output jack. See the diagram below for two Jazz Bass pickups
wired in parallel. This is normal configuration for Jazz
bass and two pickup basses, like the G&L 2500.
There are some important things here to note.
First, the pickups are actually out of phase. When both pickups
on a Jazz bass are turn up full on, the pickups cancel out any hum that
may be in the area. If you use one coil only, it will be in
single coil mode, and you can pick up hum. If you like the sound
of only one coil, and hate the hum, try using a split coil Jazz Bass
pickup, and wire them in hum-bucking mode. Dimarzio make these, and
they are a very good sounding pickup. I have used them on
previous Jazz Basses, and they work well. I especially like the
adjustable magnetic pole pieces, which are easily adjusted with an
Allen screw driver. Secondly, the control knobs shown (above) are
wired in the Jaco Pastorious prefered fashion: Volume, Volume,
Tone. The standard method is to have: Volume, Pan, and
A very important note here is to ground the bridge.
If the bridge is not grounded your bass will almost always hum when you
are not touching the strings. If you still have hum problems you should
also have, or should install brass plates under the pickups, and have
them connected to the common ground, usually on the back side of the
volume and tone pots. Make sure that these plates do not short
out the pickups. You can insulate these plates with electrical
tape or some other insulator.
P-Bass pickups are split coil type of pickup. The
two coils are wired in series, in most cases. However, you can
wire them in parallel too, which will make the sound brighter, with
less bass. The recommended wiring practice is to wire them in
series so that the coils are out-of-phase with each other. This
practice causes the pickup to become a hum-bucking (hum-canceling)
pickup coil. The advantage in this practice, is to make it immune
to outside electrical noise, which is a great plus for any bass.
Of course, you can change the pickup
wiring to single coil with these, by switching the wiring on one of
the coils. Usually, the coils come with color coded wire
connected to the coil terminals. Some coils use Red and Black,
while others use White and Black.
Below is a diagram showing how a standard P-Bass split
coil pickup is wired as hum-canceling pickup. The pickups are wired in
series. (For another example as having them wired in parallel,
Notice that the split coils are actually
out of phase here. It does not matter in this case that the coils
are out-of-phase, since there are no other pickups here. If the
coils are wired in-phase, then it becomes a single coil type of wiring,
and you can expect to hear hum when your are near electrical fields. If
you wish to add a J-Bass pickup in the bridge position, you will likely
need to wire the P-Bass as a single coil, unless you thought ahead to
by a split coil Jazz Bass pickup, as mentioned earlier.
Back to the Pickup
Back to the Home Page