[sdiy] CGS30 BPF modded for guitar use
davekendall at ntlworld.com
Sat Nov 13 21:43:41 CET 2010
Mad idea I know, but it's a request from a guitarist mate. I want to
find a way to mod this circuit
for use in a guitar stompbox. FWIW, I believe the circuit to be the
same as, or a near clone of the roland SH5 BPF.
As noise levels are not critical for his intended use, for power, I
guess I could use a resistor divider with a 9V battery to, generate
±4.5V, with the centre tap to GND on the PCB, and something like a 47uF
cap between the centre tap and 0V on the battery (which is now -4.5V on
I 'll need to attenuate the level after the effect, which will have
quite a lot of gain, in order to approach unity gain at the output.
Question is, keeping a 1K output impedance, how could I alter values in
the circuit to achieve this? I don't understand the circuit , and I
guess I could always do the obvious, and use a voltage divider at the
output using the 1K final output resistor as one half, and a pot or
fixed resistor to GND as the other half of the voltage divider, but I
suspect that might have a big effect on the output impedance - I don't
know if that's a real problem or not. The output will directly drive a
guitar combo input.
Would such a voltage divider make potential problems for a guitarist?
Any thoughts welcome.
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