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 Tone.
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
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, check out
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.
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