DIY piezo buffer preamp

Discussion in 'Amps and Cabs [BG]' started by paintandsk8, Jan 3, 2005.

  1. paintandsk8

    paintandsk8 Pushin' my soul through the wire...

    May 12, 2003
    West Lafayette, IN
    I really want to build my own piezo buffer preamp. I am taking some electronics classes so I have a basic working knowledge of electronic principles, but i am still confused on a few things.

    Here is a schematic of the type of circuit i want to use.

    Look at the two at the bottom of page 8

    My main question is this. Whenever i think of audio stuff I picture things with two leads. (Ex. a patch cable has two conductors). So, whenever think about building something like this i get confused because there is only one through signal path. I would be very gracious if someone would exlplain how a set of two piezos would integrate this, and then how to hook it to a 1/4 jack.

    My second question is how would I determine what input voltage i needed, and once again, a battery has two terminals, and on these schematics i only see a lead for V+.

    I thinking my basic electronic knowlege is hurting more than helping when look at these circuits :meh:
  2. okay...

    your electronics class should be covering this fairly shortly, but in the meantime...

    the voltage (v+) and signal (~) are both referenced to ground. The negative lead of your voltage source goes to ground (usually shown as the 'ground' symbol -- three dashed lines that sorta form an upside-down triangle). The ground lugs on your input and output jacks would also connect to the same point.

    in your case (and I haven't looked at the schematics you linked to, I'm just assuming it's some sort of IC based signal amplifier circuitry), the piezo's two wires would be connected to the 'ground' and the input to the amplifier circuitry. the output of the circuit would connect to the 'tip' contact of your 1/4" jack, and the 'ring' contact would connect to ground.

    now (and, again, I haven't looked at the schematics you linked to), don't go choosing some crappy LM384 type amplifier chip. pick something cleaner like a TL084 (or better).

    good luck, and enjoy your electronics class.
  3. paintandsk8

    paintandsk8 Pushin' my soul through the wire...

    May 12, 2003
    West Lafayette, IN
    thanks, it's actually a JFET based preamp, but i'm pretty sure what you said still applies.
  4. There was a long thread devoted to this subject in the pickup forum. That thread started as a question about using a piezo buzzer from Radio Shack as a pickup. As I am too lazy right now to find the thread, go search for "piezo buzzer" in the pickup forum.