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Piezo contact microphone help!

Discussion in 'Pickups & Electronics [BG]' started by giuseppecaporus, Mar 5, 2014.

  1. giuseppecaporus


    Dec 19, 2013
    Hi guys I want to build a custom bass with a split coil pickup and a mm pickup and 4 piezo connector (2 under the neck and 2 under the bridge) , the piezo connector are connected in pares in a 3 way toggle , the question is ...
    If I don't want a piezo buffer can I connect the to a volume pot an the connect to the blend ?
    Would it be better than without ?
  2. bassbenj


    Aug 11, 2009
    What do you mean "better"?

    Added piezo pickups is an interesting experiment, but you can't run bass piezos without a buffer (if you want any bass frequencies out of it).

    The Piezos must be looking at at least 10 meg Ohms! And you can switch them as you suggest, but be ready for some loud thumps and pops when you do it! This is because Piezos are capacitive and hold a charge which causes noises when you switch. A buffer circuit that is a good start on the interface you need is made by Fishman and is called the "power chip" even though it isn't a chip and really provides no power! It's a kind of volume control and circuit bard kind of deal.

    I'd URGE you to try these ideas on an inexpensive bass first and get them working the way you want, before you start drilling on a custom bass.
  3. JustForSport


    Nov 17, 2011
    Way good advice.
  4. Aside from it being a waste of time to even consider a passive system for piezos, because of the effects of amp input impedances spec'd for lower output impedance sources, and the effects of cable capacitance on piezo circuits; note that there is no way to mix piezo and magnetic pickups without buffering. The magnetic pickups basically short out the piezos, because their output impedance is so much lower.