Piezoelectric pickup in a jag???

swimdeeper · Post by **swimdeeper** » Wed Jan 28, 2015 3:30 pm

I had a great but probably very stupid idea. Put a piezoelectric pickup in a jag to add another sound to it's repertoire. I had the idea to put the actual transducer in the tremolo cavity and wire it up so that it goes through the lead circuit, and has it's own switch. I can use the switch cover from a Bass VI for this.

But I'm not sure how I would go about wiring it up, and I'm not sure if it's a good idea or not. Any advice would be appreciated

-joe

NickS · Post by **NickS** » Wed Jan 28, 2015 3:44 pm

What sort of pickup are you looking at? I don't see how you can put a bridge saddle type transducer in the cavity. They generally need a preamp, which you may be able to put in the cavity.

NickS · Post by **NickS** » Wed Jan 28, 2015 3:47 pm

A quick Google result:
>cough< http://www.offsetguitars.com/forums/vie ... ?f=7&t=454 >cough<

The best result I got was using http://www.stewmac.com/shop/Electronics ... matic.html but it waas quite some serious work to modify some studs and get this bridge in place on a Jazzmaster.

swimdeeper · Post by **swimdeeper** » Wed Jan 28, 2015 3:58 pm

I read that, but I was more concerned about wiring options, I was planning to put in something like this
http://www.ebay.co.uk/itm/Uncased-20mm- ... 46102989f1
but skip a preamp, more so that I can slightly change the pickup sounds with it than as a pickup in its own right

NickS · Post by **NickS** » Wed Jan 28, 2015 5:25 pm

Ah, my son used those as triggers on drums for a project on his sound engineering course. Well, actually he bought piezo sounders and broke them out of the cases, it was cheaper.

So, looking at the specs, the capacitance is 12 nF each (0.012 uF) or 15 nF depending on whether you believe the first or second page, and the impedance at a resonant frequency of 5.5 +/- .5 kHzkHz (or 6.8 kHz +/- .7 kHz) is <200 ohms (or <300 ohms).

OK.. you say wire it through the lead circuit; in series would cut the bass as you'd effectively be running through a .012 uF cap. Putting three in series would reduce the capacitance to .004 uF and make the bass cut worse. In parallel with the p/up would effectively dump the treble to pretty much a short at the resonant frequency, so you might want to experiment with different value resistors in series with the piezo. There may be some interesting effects as the inductance of the pickup resonates with the capacitance of the piezo element (this will be damped by a series resistor), and the self-resonant frequency of the pickup may be around the same as the piezo element. I'm not sure you'll actually get enough output from the piezo element to be significant. Overall, I'm going to stick my neck out and guess it will sound crap; but don't let me stop you experimenting and let us know how it goes (do an demo video).