Piezo buzzers as pickups: impedance solution?

[bobbletrox]

I play upright bass and have found that alot of rockabilly guys use the guts of piezo buzzers wired to 1/4" jacks as pickups for their basses.  It got my attention because commerical piezo pickup systems for double basses are really expensive and was wondering what kind of circuit would really help get the most out of these cheap buzzers.

http://www.oz.net/~walterh/basspre1.htm

I found this page that has a circuit that raises the impedance of piezo pickups (the guy etched the PCB with a dremel!), so I was thinking maybe something like this in conjunction with a simple boost would be a cheap alternative to the commercial preamps.  A simple two pot mixing stage in front of it could let you use two buzzers wired to a stereo jack for an even better response.

I'm just thinking out loud here.

[toneman]

just tape the Piezo-trnasducer to your guitar or bass.
Use any of the JFET boosters at AMZ or anywhere.
The real trick is getting a wire on the piezo.....  
Barcusberry used to make a "HotDot" piezo.
I installed one in my old Epiphone acoustic.
staypeezode
tone

[bobbletrox]

I getcha.  So just a fet booster should do by itself because they're already high impedance?

This is a pic of a DIY transducer someone made from a buzzer -it's pretty impressive!

[elberto]

Buried in Harmony Central somewhere is an archive of a long thread devoted to making pickups from piezo buzzers.

There's a specific radio shack part that works well.  I've made one for an electric guitar and one for a cello, they both sound great, straight to an amp or DI'd.

[bwanasonic]

I made extensive use of a  DIY piezo buzzer pickup back in the mid 80's. Not sure about any impedance issues, as I just ran the piezo into my 4tk cassette. I do remember wiring a cap between the inner and outer rings of the piezo, but  I don't remember what value.

Kerry M

[bobbletrox]

The main complaint from upright players seems to be that the signal is thin sounding when fed directly into an amp and that it's got some crazy mid-range hump.  The transducer itself seems to work fine, but the resulting signal sounds crap.   That's why I was figurin' mabey a simple circuit to improve the impedance would do and then the signal could be eq'd on the amp.

The circuit on that website raises the impedance while remaining at unity gain.

[Mike Burgundy]

JFet boosters will do, MOSfet boosters may even improve on that (possible input impedances of 10M, or even higher but I doubt thats benificial). Follow that wit, say, a 2 or 3 band parametric and voila.

[birt]

if all this is cleared out, can someone make a DIY article or something about it cos it would be a really great project but i don't understand a lot of it right now :?

[David]

I did this with my 6-string acoustic this past summer.  IMHO, it worked quite well.  I need to resolder it and make the installation permanent.  Mine is installed on the outside of the guitar.  Function is more important to me than form, so this is not an issue.  I spent quite a while finding a good place to locate the pickup.  After installation, it was quiet, real high output, and no impedance problems I could detect.  Sometimes I used a little bit of EQ to sweeten it, but this isn't always necessary.  I'd say the JFET preamp, if even needed, would work nicely.

[bobbletrox]

There's a easy to understand article on how to make a piezo pickup from a buzzer on this page, birt:

http://users.aol.com/bluemuse/pickup.html

Then just plug it into one of the boosts that have been suggested!  As for the eq section, RDV's Heavy Metal Pedal has a parametric bass/mid control and a passive treble, and Mike Burgundy posted this eq with a parametric mid control;

http://users.balpol.tudelft.nl/~Burgundy/bin/schem/parametricguitarhybrid.gif

I reckon the boost alone would be a good start, but a parametric eq would let you hone in on those mids.

[petemoore]

Interesting, and looks to be worth a try !!!

[Travis1010]

Hello, let me first say this a really cool message board and has helped me out a lot! I have made a few these contact/piezo pickups in the past and I am currently making one for my upright bass. In the past, I used a Piezo pickup from radio shack on a cello. I just soldered the leads coming from the piezo to a 1/4" jack and it sounded decent. It is really hard to get a good sound from these pickups, placement is key. I use a really expensive contact pickup on a really nice upright at my college, and even it doesnt sound great. Interestingly enough, the $200+ pickup system at my school and the $5 radio shack system I made look almost identical.
Travis

[bwanasonic]

I'll have to find that article that I based my DIY piezo on, as it suggests cap values to tailor frequency response (trim some of the *icepick-in-the-ear* frequencies). I also remember buying just a *raw* piezo element (no enclosure/wires, etc.) from RS circa 1984. Don't know if they still carry it.

Kerry M

[Ivan]

Hi everyone long time reader, first time poster! Awesome forum with only one drawback: it's highly addictive!!!

Anyhows back in the day when I didn't have an electric guitar, I searched for a way to cheaply "electrify" my acoustic. A piezzo speaker ripped out of a musical greeting card soldered to a shielded guitar cable was as cheap as it gets! You can also get piezzo buzzers from R.Shack and get the crystals out of those. As someone already mentioned soldering the crystal is the hardest part but there are several good tutorials on the web. The sound was pretty decent... especially when you factor in the costs!

At some point I wanted to take things further but never got around to it, however I found some schematic that might be useful on http://www.anubics.com/. Since I can't open the pictures on anubics for some reason I'll temporarily host them here:



Schematics:
http://img.villagephotos.com/p/2004-11/883854/Barcus_3000A.gif
http://img.villagephotos.com/p/2004-11/883854/Ovation_Preamp.gif

Again I have no experience building these but they might be useful. Good luck!  

[bobbletrox]

Schematics:
http://img.villagephotos.com/p/2004-11/883854/Barcus_3000A.gif
http://img.villagephotos.com/p/2004-11/883854/Ovation_Preamp.gif

Again I have no experience building these but they might be useful. Good luck!  

Thanks for posting those!!  Those are some cool little circuits.