#1
Hey,

Im new here, I made this account just to present this problem Ive been having, and Ive been totally baffled by what I have on my hands. Ill just tell this like a story.

About 6 months ago I had learned about piezoelectric pick ups and I had decided I needed one on my bass guitar (fretless jazz bass). So I bought a piezoelectric bass guitar bridge pick up off Ebay. I Installed it myself, and built a little wooden box that contained a volume pot I harvested off my old Squire Start and a output jack. I dont know anything about circuitry, but I found a diagram off the internet and used my neighbors Sodering Iron and build it. Now my bass has two outputs, one for the two magnetic pick ups and one for the piezo electric pick up.

On my pedal board I mix the signals back together on an A/B pedal, each out put has its own distortion pedal.

Now Ill talk about my problems, and where I get confused.

The piezoelectric pick up is passive, and it has a lot of treble. It lacks bass frequencies. Which is my first problem. But I was fine with this as long as I could mix the signals and get a lot of the magnetic pick ups in the output.

But this gets really confusing, the volumes get all screwy between the piezoelectric pick up and the two magentic pick ups.

Just the magnetic pick ups turned on, its loud, and fine.

When the magnetic pick ups and the piezoelectric pick up are turned on, but the piezoelectric volume knob is at zero, its just a really weak signal from the magnetic pick ups.

When I have the magnetic pick ups, and the piezoelectric pick up turned on, then I have to keep the piezoelectric pick up at a really low volume, because it quickly overpowers the magnetic pick ups.

If I plug in just the piezoelectric pick up I get a ton of noise thats louder than my actual signal. But I dont get this when I plug in both pick ups. Actually, that sounds really problematic, I just always have both plugged in so I never deal with this.

Did I do something wrong? How can I either, get more signal strength out of my magnetic pick up, or if I didnt install my piezoelectric pick up, fix it/get more bass out of it?

I dont know anything about this kind of stuff. Hopefully this isnt too confusing.

Thank you for any insight you can provide!
Attachments:
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Last edited by Tungsten_man at Nov 16, 2009,
#3
You need a preamp for the piezo. The piezo is a drastically different impedance than the magnetic pups, so that's why all the screwy shit happens. you just need a preamp with a buffer to 'match' the impedances.

also a simple a/b box won't properly mix the signals. you can build a simple mixer as well.

nice looking bass btw.
#4
Quote by Invader Jim
You need a preamp for the piezo. The piezo is a drastically different impedance than the magnetic pups, so that's why all the screwy shit happens. you just need a preamp with a buffer to 'match' the impedances.

also a simple a/b box won't properly mix the signals. you can build a simple mixer as well.

nice looking bass btw.


Not to hijack this thread or anything, but I've been considering doing the exact same thing to a bass of mine. What pre-amp would you recommend for this specific application?
#5
Quote by Invader Jim
You need a preamp for the piezo. The piezo is a drastically different impedance than the magnetic pups, so that's why all the screwy shit happens. you just need a preamp with a buffer to 'match' the impedances.

also a simple a/b box won't properly mix the signals. you can build a simple mixer as well.

nice looking bass btw.


Thank you so much.

Ive never worked with a preamp before. Is it pretty straight forward though? Is it like, I just need to go out a buy "a preamp"?
#7
Also, what does it take to build a mixer? I bet its really simple technology, I just dont understand what it takes to build one. How is it different from an A/B swtich?
#8
No idea, jerry.

TS: you can buy one (prolly the best option) or you can build a simple one.

mixers are very simple. you can build one if you know how to read schematics and are familiar with basic electronics. i have3 a schem for a very simple 4-channel mixer if you want it. you can add or remove as many channels as you want easily.
#9
Thank you Jim. In the next few weeks, Im going to be following your advice exactly.

Yeah, I'd really appreciate those schematics. Im pretty inexperienced, but I think I could figure it out. I think I have a rough idea already of what those shematics look like.

Btw, nice squier. How do you feel about all those pick ups? I find all those pick ups interesting.