choosing piezos

anonymous278347457 · #1 03-23-2006, 11:02 AM

Im going to Maplins(UK equivilent of radio shack i thing) to buy some parts to try out some mods on my old bass.

Im mainly looking for a cheap piezo that i can mess around with.
http://www.maplin.co.uk/module.aspx?...=3202&doy=23m3

Are these the things that i need to put on my bridge?

and if so, do i need 4 or just 1?

thanks,

Verne Andru · #2 03-24-2006, 10:39 AM

I'm playing with some that are similar. Come in a package of 10 for $4 at my local electronics store. I'm using them for an archtop project [acoustic] but have tacked them to my solid bodies [bass as well] and they seem to work great. Trickiest part is where to place them - you just have to experiment until you get it right. I tried 1 by itself then 2 in series and parallel. They react like speakers - 2 in series was too hot and started distorting. 1 was kinda nasaly. 2 in parallel sounds best so far but I have not tried more than that yet.

fender_mod · #3 03-25-2006, 12:22 AM

Quote:

Originally Posted by Verne Andru

I'm playing with some that are similar. Come in a package of 10 for $4 at my local electronics store. I'm using them for an archtop project [acoustic] but have tacked them to my solid bodies [bass as well] and they seem to work great. Trickiest part is where to place them - you just have to experiment until you get it right. I tried 1 by itself then 2 in series and parallel. They react like speakers - 2 in series was too hot and started distorting. 1 was kinda nasaly. 2 in parallel sounds best so far but I have not tried more than that yet.

do you wire those into volume and tone pots in a solid body or just a direct output?

Verne Andru · #4 03-25-2006, 11:49 AM

Quote:

Originally Posted by fender_mod

do you wire those into volume and tone pots in a solid body or just a direct output?

I tried wiring them to pots then out, but the signal got real noisey and the pots didn't do much. On the archtop I'm running them to a Fishman Powerjack which has a built-in preamp, then to the pots and then out. Works great with the preamp and I find piezo's definitely need some tone tweakability. I find there isn't a whole lot of difference in sound going straight out or through the Fishman other than the ability to adjust volume and tone. For a solid-body I'm thinking of putting the piezo's under the pickups mounted to the body then to a pre-amp and then out. I tried a quick under the bridge setup, but the sound wasn't as good as just mounting them to the body. As I said, placement appears to be the key to good sound. There are a few schematics around for real simple JFET piezo buffer/pre's that look like they'll do the trick.

fender_mod · #5 03-25-2006, 02:20 PM

the preamp idea sounds like it would be a cool thing to do, i think ive seen them on ebay for around 60$, could be a project worth considering

Verne Andru · #6 03-25-2006, 04:39 PM

You don't have to spend that much. The Fishman Powerjack was around $28 at Music123 [open stock but who cares]. All it is is a JFET preamp in an endpin jack nicely packaged. The powerjack allows 2 different pickups - one that goes to the preamp (the piezo) and the other that it passes through (humbucker/mag) giving you a stereo feed out of the guitar. Since I needed an endpin jack for my archtop anyway and I'm putting in a floating humbucker along with the piezo it is a real slick way to go.

Do a google on preamps and you'll find ton's of them. If you know your way around a soldering iron the parts are cheap and the circuits are really simple. Here's a few to get you started:

http://www.cafewalter.com/cafewalter...p1_project.htm
http://www.commlinx.com.au/Preamp.htm

These are my faves:

http://www.scotthelmke.com/Mint-box-buffer.html
http://www.till.com/articles/PreampCable/index.html

I really like the idea of the preamp in the cable for applications where you don't have room in the guitar. The Mint-box-buffer looks like a slick circuit and the guy will even sell you one pre-built for around $20.

This isn't rocket-science. All you need to do is some impedance matching and buffering and let the piezo's do the rest. Once I get the archtop done I'm going to put a bunch of piezo's inside the body of my Dano double-neck. I would do my bass but I'm so happy with the tone of my Q-Tuners I don't really see the point.