The PZP-1 Piezo Buffer is a high impedance buffer preamp, using 100% discrete class-A circuitry. Designed expressly for the Fender™ Precision acoustic/electric and HMT basses, it can also help other instruments with piezoelectric pickups. If you thought piezo pickups had to sound “clacky”, weak, and trebly, think again! Properly buffered, the Fender piezo pickup has bass that’s miles deep, yet it still cleanly captures all the warm woodiness of this semihollow-bodied instrument.
The PZP-1 started out as a way to improve the sound of my own Fender A/E, the second bass I ever owned. I loved the playability of the bass but never found the piezo bridge pickup to be useful on its own. Eventually I got frustrated, took it apart, and discovered that the electronics in this bass were designed for two magnetic pickups, not a mag and a piezo. I came up with a fix, and put up a web page describing it so other hobbyists could follow in my path. A few people built it, we exchanged information, and the circuit evolved over time. A number of people more interested in playing bass than in soldering asked if I could sell them one ready-made. And finally the answer is yes!
The PZP-1 has flat frequency response across the audible range, so it is suitable for many instruments other than bass. People have used PZP-1s in electric violins, hurdy-gurdies, upright basses, mandolins, cigar box guitars, and at least one erhu, just to name a few examples.
Please note that a number of other folks are selling piezo buffers based on an earlier and simpler version of this circuit. The present version has somewhat lower distortion, lower noise, and is better able to drive low impedances than the older circuit could. All versions of this circuit are in the public domain and copying is welcomed. So far I haven’t seen anybody else selling this version, though.
The PZP-1 fits inside your bass and shares the same battery used by the existing electronics. Because of this, installation does require some soldering, similar to other aftermarket preamps or replacement pickups. If you have questions about whether you’re up to it, take a peek at the installation guide below.
The PZP-1 is also available with only one battery clip for use in an instrument with no other active electronics, and can be mounted in a mint tin for outboard use. Contact me for details.