Underwood Bass Pickup - Bridge Mount

A message from the Underwood Family
Underwood Pickups is a family business and has been for over 35 years. We hand assemble and test every Underwood Bass Pickup to assure the highest quality possible.

The Underwood pickup was designed by Don Underwood in the early 'seventies, to prove theories he developed about the operation of the viol bridge. His first prototypes worked so well that he decided to market the device and applied for and obtained patents.

Major bassists throughout the world use the Underwood, some for as many as twenty nine years. It has become the standard by which other bass pickups are judged.

Proper Fitting of the Underwood Transducer
Underwood Bass Pickups are occasionally returned for repair or warranty replacement displaying indications of improper installation or maintenance. The installation instructions supplied with the pickups discuss the proper way to avoid applying too much pressure on the transducer cases.

Final fit should be checked with FULL STRING PRESSURE ON THE BRIDGE! I have been told that some installers are fitting the transducers with the bridge removed from the instrument. While this is a professional and expedient way to achieve a "true" slot, the added pressure of the strings will cause some collapse in the bridge height and thus close the slots slightly. If the transducers are in place when the string tension is brought up, damage can occur to the pickup. And worse, a wing could pop off, ruining the bridge. If the bridge is removed for fitting, please allow plenty of room for the transducers and use shims for the final fit.

If the pickup was installed with the proper amount of pressure in the beginning, it is possible for the bridge to take on moisture (especially a new bridge) and pinch the transducers to the point of damage. The transducer units should be
installed with just enough pressure to insure that they will stay in place when the bass is played or moved. I call it "finger tight", meaning that the units can be easily moved about with the fingers. It is often necessary to file or sand the wings of the bridge to open the slot enough to accomplish the correct fit.

If the fit is too loose, paper or card shims can be used to obtain the correct pressure. Be certain that the shims are installed under the transducer case, between the case and the leg of the bridge.
If the transducer case has been under too much pressure, the black filler material around three sides of the case will protrude, sometimes showing black edges of the internal damper pad protruding. Once the pickup has reached this
state, there is no recovery. If you then lighten the pressure, the internal pressure contacts will become intermittent, causing pops and static sounds. Additional pressure will sometimes stop the noise but the fact is that replacement is the nly real choice.

If you experience loss of frequency response, intermittent noise, too much sensitivity (leading to feedback) or dropout of signal from either side, check the fit for too much pressure. We try very hard to build a solid, dependable pickup. If there is a failure we want to correct it, so please let us know.

Don Underwood

10/20/06