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Double Bass How to make a piezo preamp
- Thread starter fdeck
- Start date
You know that you need to use certain resistor values for the 2N5486?
And these JFETs are good for a simple buffer without a phase switch but the phase switch needs a PN4416 or 2N4416 (or the SMD version of it).
So you can build FDecks Quick’n’dirty buffer with it but need to change the two resistor values (or even change one of them to a zero Ohms cable connection).
(Maybe the is a direct connection on the bottom, then only the resistor going to the voltage source may need to be changed.)
I’m not at home now and have no time to look things up either, but to get an undistorted output you may even have to measure the JFET to get the optimal response.
I have used a free spice program (the one Francis has used, cannot remember the name now) to simulate it, but as Francis had explained somewhere, the manufacturing of the JFETs has tolerances that may need to measure the JFET together with the resistor(s) and the voltage source to get the optimal resistor(s) for it.
It took me a while to understand how to use the spice program. An impedance buffer is simple project to start with and now there is a larger collection of JFETs available than when I started using it, but you may need some time until you understand how to use it.
And these JFETs are good for a simple buffer without a phase switch but the phase switch needs a PN4416 or 2N4416 (or the SMD version of it).
So you can build FDecks Quick’n’dirty buffer with it but need to change the two resistor values (or even change one of them to a zero Ohms cable connection).
(Maybe the is a direct connection on the bottom, then only the resistor going to the voltage source may need to be changed.)
I’m not at home now and have no time to look things up either, but to get an undistorted output you may even have to measure the JFET to get the optimal response.
I have used a free spice program (the one Francis has used, cannot remember the name now) to simulate it, but as Francis had explained somewhere, the manufacturing of the JFETs has tolerances that may need to measure the JFET together with the resistor(s) and the voltage source to get the optimal resistor(s) for it.
It took me a while to understand how to use the spice program. An impedance buffer is simple project to start with and now there is a larger collection of JFETs available than when I started using it, but you may need some time until you understand how to use it.
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