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Just picked up some polymer film transducers. Haven't hooked them up yet, but I'm told they make great contact mics. It's the same stuff used in many guitar pickups. Hopefully I'll have some time to solder them in the next two weeks or so. I'll have recordings up once I finish putting them together!

Has anyone made one of these before? Any tips?

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Awesome idea! Can't wait to hear about your results… –  Jay Jennings Aug 16 '10 at 22:48
    
I second that statement! –  Utopia Aug 17 '10 at 2:26
    
Where did you get them? Can you provide model numbers or links? –  endolith Oct 11 '10 at 14:56
    
I have tried to build a PVDF contact as I would when using a piezo disc. But it's not that easy. The PVDF tab requires shielding so it won't pick up unwanted signal. Even then I have not had success. the PVDF film is a different animal requiring different treatment of which I have been unable to find direction for in the ethernet. –  user822 Jan 20 '11 at 16:42
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1 Answer 1

Piezoelectric pickups need a preamp with a really high input impedance, preferably on the pickup end of the cable rather than the amp end.

Piezos have a very high (capacitive) output impedance, so they need to see an even higher impedance at the input of your preamp, or they'll be prone to interference and low-frequency roll-off.

(A 500 pF pickup, for instance, has a 6 MΩ output impedance at 50 Hz, so even if you plug it into a "high-impedance" 1 MΩ guitar input, it will have dropped off by -17 dB at 50 Hz.)

http://liutaiomottola.com/electronics/bassducer.htm

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