Hi all!
I have a Charvel/Jackson in which I have a new fretless ebony/wenge fingerboard installed (a whole other story...).
Anyway, I equipped it with two RS-style piezo pickups and have a few questions for those willing to help me
1) They're actually three piezo buzzers - two wired in series installed under the bridge and one (bigger) right under the part of the fingerboard going over the body (doesn't show itself much that way
Wiring the two "pickups" in series was causing a serious amount of hum - has anyone any idea as to why that might be?
Anyway, I installed them for now in a series-parallel configuration: 1+2 are in series, 3 is parallel to the two, where 1 and 2 are the bridge piezos and 3 is the neck piezo. After those pickups I have a simple JFET buffer - powered from the same 9V battery as the EMG pickups.
I then re-soldered the tone control knob to serve as the piezo volume.
2) The signal from the piezos is still quite weak compared to EMG active pickups (when separately turned on). Since I heard it's expected from piezo to have a bigger signal then magnetic pickups I just want to make sure - is the lower volume level normal for solid-body instrument? If so, what preamp would you recommend in the DIY-department? I'd like to brag about having done all the mod myself
Would an op-amp do the trick? Or would for example a 2-JFET preamp have some advantages?
3) I'm sure it's caused by wiring, but when I turn the piezo volume up, the mag pickups turn noticeably quieter. I wired the pot the same way as two other volumes - center leg to piezo output, one to ground and one to the hot(tip) of output jack - together with other two pots' outs.
Should the piezo output be wired the same way as each magnetic pickup? What pot value would you recommend? It's now stock value - 25K. I think it *might*
be too small, but if that effect isn't caused by the pot value, I'd like to know it before I buy a new one
4) although I use a 20 MOhm input impedance in the buffer, the output from piezos is still very bright without much lows - or at least it seems so compared to active EMG mags..Could it be a transistor fault? Or some other configuration issue?
I know there's a lot of threads on piezo, but I couldn't find information that specific - so if anyone has anything to say - please do
Thanks a lot,
Kuba
P.S. Sorry for the loooong post
