Tuesday, February 19, 2013
Piezo pickup preamp for musical instruments
I built a single jFET preamp for my mate's double bass which is fitted with a piezo pickup under the bridge. I couldn't make it work properly and therefore this OPAMP based attempt. Mustard caps are all the rage with pedal makers and I just happened to have about 6 from my early electronic days mostly 0.1uf. Mustard cap on the input and polypropylene on the output.
The paint job is a poor attempt at hammertone. Right colour no hammer?? The OPAMP is my fav. OPA2134 and is running at 18V. Input impedance is a ridiculous 10M. There appears to be good gain and the pot seems to enhance treble as it is turned up. I work both sides of the proto-board and even cut a track for compactness.