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I have an electric cello that was originally equiped with active pots and a piezo pickup. I removed the active pots and put in a passive circuit based on a fender precision design. The tone control and volume control don't work together very well. Is there a right way to wire the piezo pickup without the active pots?
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Piezos need an active buffer as they are very high impedance. Regular value pots will load down the pickups. Piezos also don't sound very good plugged into an amp without the active buffer.Originally posted by nbtone View Post
Why did you remove the active circuit?It would be possible to describe everything scientifically, but it would make no sense; it would be without meaning, as if you described a Beethoven symphony as a variation of wave pressure. — Albert Einstein
http://coneyislandguitars.com
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I'm using a tube preamp, and the transistor preamp is not a good thing for the tone quality. I'm getting a better tone quality without the active pots, but the controls aren't working the way they should. There is one control setting where the tone is best, but turning either control up or down takes away from the tone. It's strange.Comment
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You are getting better tone because it's probably not a god sounding pickup to start with, and the lack of a very high impedance preamp is smoothing the high end out.
You wont be able to use passive controls with the piezo however.It would be possible to describe everything scientifically, but it would make no sense; it would be without meaning, as if you described a Beethoven symphony as a variation of wave pressure. — Albert Einstein
http://coneyislandguitars.com
www.soundcloud.com/davidravenmoonComment
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Some tube amp preamp designs have very high input impedance. Get some 5 meg ohm volume and tone pots. 250k or 500k are WAY too low for this. You really need a good quality cable with low self capacitance. Keep this as short as possible.Comment
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I was going to suggest 5 or 10 meg pots, but I've never tried it so I wasn't sure.Originally posted by David King View PostIt would be possible to describe everything scientifically, but it would make no sense; it would be without meaning, as if you described a Beethoven symphony as a variation of wave pressure. — Albert Einstein
http://coneyislandguitars.com
www.soundcloud.com/davidravenmoonComment
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Do I use the same capacitor in the circuit. I'm copying a fender precision bass as a model for my cello circuit. You are saying to just use a 5 Meg pot in place of the 250K pots. Is that right?Comment
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That's what we are saying.
What you are trying to do is pretty unorthodox. These pots aren't easy to find and unless your amp was specifically designed to handle piezo output you probably aren't going to be happy with the results.
Piezos put out a lot of voltage at very low current. Most amps are designed to handle magnetic pickups that have very low voltage output with more current.Comment
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I'll try that! Thanks alot.Comment
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I was looking in the new Nuts And Volts magazine, and they mentioned these preamps:
http://secure.oatleyelectronics.com/...roducts_id=722
http://secure.oatleyelectronics.com/...roducts_id=784
Do you think either one would make a better preamp for the piezo pickup?Comment
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