Bridge Pickup Base Plates

There is quite some confusion about the Tele bridge base plate. Everybody tries to explain the reason for this baseplate with only one function, but this baseplate has, in reality, 3 different functions:

A. Ferromagnetic functions,

B. Electrodynamic functions

C. All metal plates provide extra shielding.

#1 -- Only the steel baseplates corresponds to function A, B, and C.

#2 -- Brass, copper and aluminum baseplates have no ferromagnetic functions, and therefore, only correspond to function B and C

#3 -- Alloys of the 300 series stainless steels have neither ferromagnetic nor electrodynamic functions and therefore, only correspond to function C.

Brass Base Plate - notice that the base plate also serves as the ground for the bridge pickup.

Function A

Leo Fender used copper-plated steel baseplates on the Tele bridge pickup to stabilize and to increase the magnetic force of the relatively weaker Alnico 3 slugs. The ferromagnetic steel plate increases the inductance of the coil (like increasing the number of turns on the coil).

The steel baseplate also transmits from the steel bridge mount via the steel mounting screws some of the body vibrations into the pickup, resulting in that typical Tele twang. As a negative, this is also the cause of microphonic squealing at high volume levels.

Function B

Baseplates made of steel, copper, brass or aluminum are the cause of eddy current interference. Eddy currents shift the resonances toward the lows, resulting in a fatter, more pleasant tone, especially in the bridge position. If you don’t want to increase the inductance of the coil and the magnetic force of the magnets, aluminum and brass baseplates are ideal to fine tune the tone of single coil pickups.

These baseplates can be very effective on traditional single coil pickups with alnico slugs, but on many different designs, the result can be disastrous.

Also, the thickness of the baseplate is very important -- if the plate is too thin, the effect is very little, but if the plate is too thick, you may end up with a muddy pickup. For excellent results, keep the thickness of the plate between 1/32” and 1/16” and make sure that the plate is firmly attached to the pickup.

Submitted by legendary pickup manufacture/inventor Bill Lawrence
www.billlawrence.com