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  • J Lee May 28, 2014 at 9:04am
    Ok, so the rod piezo/jack assembly finally arrived.
    I assumed it was as simple as locate the jack, cut the prize rod into the bridge and away you go. However.....it doesn't appear to be working...have I missed something? Does it need to be grounded perhaps. If so, how would I go about doing that?
    • The Capo Kid > J Lee May 28, 2014 at 9:42am

       The rod piezo needs to be under compression to work , I fit mine in a slot in the bridge and the saddle sits on top of that and the strings on top of that , but the piezo needs to be a snug fit not too tight for it to work well , post some pics if you can all ways helps others to help you .

  • John Sawyer May 8, 2014 at 11:54pm

    My only add would be:  Since piezo's have a high impedance, you should use a high-value pot... Like 1MOhm, or 500kOhm, and "audio taper"...

    There's an article here somewhere on using vol. controls with piezos, and the recommendation was to use a very small capacitor or you roll off the high frequencies with the volume control... I'll go see if I can find it...  I would assume it applies to Rod piezos, but I dunno...

  • The Phrygian Kid May 8, 2014 at 12:15am
    You can certainly add a passive volume control tho...

    Rather than copy paste you one of Mr Ted's famous diagrams and that's it (as is the standard response here to this question) let's talk basics, how a volume control works..

    There are two basic ways to use / view a potentiometer..
    1 as a voltage divider
    Or
    2 as a variable resistor

    Approach 1.. A voltage divider..
    There are three lugs to solder a wire to on your potentiometer..
    Imagine some current entering thru the centre lug..
    If the pot is turned fully to one end, the current all leaves thru one of the side lugs. If the pot is fully turned the other way the current all leaves thru the other outside lug. If the pot is somewhere between the two extremes then the current is divided between the two outside lugs accordingly.

    To make a volume control using this approach we can solder one of the outer lugs to ground, and the other to the hot output from the pickup/pickup selector... And we can connect the centre lug to the hot side of the output jack.
    This is the more common approach to a passive volume control.

    Approach 2, variable resistor.
    Use only two of the lugs, the centre and one of the outer ones. The third lug is unused. This is like a water faucet. We use this approach when there is more than one volume control, like on a Gibson guitar type circuit because otherwise turning one pickup down can turn both of then down as signal is sent to ground.
    • J Lee > The Phrygian Kid May 8, 2014 at 12:34am

      Great explanation!...as always. Thank you so much. Really appreciate it.

  • David McQueen May 7, 2014 at 9:42pm
    Looks like a rod piezo and jack, but no preamp. Looks to me like you have to run it to a preamp or preamp/amp combo to get some gain before using a volume control. Disk piezos are really hot in that they send out a strong signal so you can have a volume pot right off the bat. My understanding is that the signal from a rod piezo is much weaker and has to be boosted.

    That being said, lots of people do stuff on this list, and most of the time it works. So someone may have a better idea.
    • J Lee > David McQueen May 7, 2014 at 10:04pm

      Thanks for your input David....certainly food for thought.

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