Piezo problem

Hi all. New to the forum so please be gentle. 
A friend gave me a tune o matic piezo which I decided to fit on a Les Paul that I made last year but I’m having issues. 
I’ve wired the humbuckers to 1 vol,1 tone and the piezo to the other vol. no preamp as I wanted to make sure everything works first. 
If only the humbuckers are wired to the jack all is good, if the piezo only is wired all good. Connecting both to the jack doesn’t work as both volumes affect the signal and are either on or off. 
I wanted the volume for the piezo separate so that I can blend it with the humbuckers. 
Ive need modding my guitars for years but I just can’t see the problem. 
Any help would be appreciated. 

Cheers
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Comments

  • RolandRoland Frets: 8591
    edited April 2019
    Pieman said:
    .. no preamp ...
    I guess this is your problem. Piezo and magnetic pickups have different resistances. Without a preamp to buffer the piezo they will interfere with each other. 

    It’s a good idea to check the piezo before going further, but at this point I’d connect in the preamp.
    Tree recycler, and guitarist with  https://www.undercoversband.com/.
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  • ICBMICBM Frets: 71960
    Yes, what Roland said - even if you wire the volume pots 'backwards' (pickup to rotor, output to top of track) so they don't both mute the sound in the middle position, the impedances are incompatible and it will completely kill the volume and tone of the piezo.

    Without using an onboard preamp, the only effective way to do it is to use a very high impedance volume pot (at least 1Mohm, preferably 2M or 5M if you can find one) for the piezo, and a stereo jack with an external splitter so the two pickup types go to different amps.

    But it's easier to accept having an onboard preamp and use a Fishman Powerchip, which is designed exactly for that purpose and still allows a split output if you want.

    https://www.fishman.com/accessories-tuners/powerchip/

    "Take these three items, some WD-40, a vise grip, and a roll of duct tape. Any man worth his salt can fix almost any problem with this stuff alone." - Walt Kowalski

    "Just because I don't care, doesn't mean I don't understand." - Homer Simpson

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  • PiemanPieman Frets: 0
    Cheers for the advice and the web link. Thought a preamp was going to be necessary. 


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