Maker Pro
Maker Pro

Piezo's. Both running them over distance and pre amps

darren adcock

Sep 26, 2016
463
Joined
Sep 26, 2016
Messages
463
Hey all.

Today I was trying to help an artist with an installation. They want to amplify water dripping on metal objects, I tested today attaching piezo discs on to them (water proofed) with simply putting a 100nf capacitor across it's contacts then running them around 15 meters each to a mixing desk then into speakers.

The results were ok, but not exactly great quality.
-Firstly we had to push the mixer to it's max as the signals were too quite. Is building pre-amps the right way to solve this?
-Secondly there was a typical ground hum that was audible. Is this from the length of the leads? A combination of the length of leads and having to turn the mixer all the way up? My immediate thought was to have the initial piezo disc and lead run short to a pre-amp then run a longer cable from there to the mixer.
-Thirdly we managed to tune into a local radio station! :-D

Any thoughts on what might be best here? We could use shotgun mic's but the discreetness of piezo discs is a preferred aesthetic.

Thanks in advance

Darren
 

Alec_t

Jul 7, 2015
3,211
Joined
Jul 7, 2015
Messages
3,211
Twisted pair cable, or screened cable, would keep noise/hum pickup to a minimum. Any capacitor would likely be more effective at the mixer end of the cable. Pre-amplification is clearly needed if you're having to crank the mixer to maximum gain.
 

darren adcock

Sep 26, 2016
463
Joined
Sep 26, 2016
Messages
463
Twisted pair cable, or screened cable, would keep noise/hum pickup to a minimum. Any capacitor would likely be more effective at the mixer end of the cable. Pre-amplification is clearly needed if you're having to crank the mixer to maximum gain.
Thanks Alec, off to look at Piezo Pre Amp circuits now and the cables you suggest.

Dunno why I didn't think about screened cable, doh!!!!! just used whatever I had lying around at the length needed today.
 

darren adcock

Sep 26, 2016
463
Joined
Sep 26, 2016
Messages
463
Ok so spent sometime looking at circuits and reading what i think is required. I found the below circuit from Elliott Sound Products....Fig 10 in this link. http://sound.whsites.net/articles/high-z.html

Is this a suitable circuit?

high-z-f10.gif
 

darren adcock

Sep 26, 2016
463
Joined
Sep 26, 2016
Messages
463
Thanks Alec. I'll order the components I need and report back if any problems.
 
Top