| FET pre-amplifier |
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pege last update april 2007- (página
en catellano) |
| Because of their high impedance, piezo transducers have the disadvantage of being very sensitiv to external noise. Furthermore, because of their limitted bandwith, the sound reproduced from any object is enevitably poor and with little body. | |
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The FET preamplifier
which I am using for this project has been designed by J. Donald Tillman.
I found his article by accident on the internet. This surprisingly simple
circuit is very efficient at reducing the tranducers sensitivity to external
noise, by converting the impedance from 10M to approx. 6K. The sound quality
was significantly improved. From a ciucuit designed originally for a 6,3mm
Jack socket, I have made a small PCB which includes a trimmer to adjust
for optimum BIAS current. |
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fotos
Holger Strauss
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