Hi, some folks ask me frequently for the 0.47 capacitors to be used in (C1 C4 C6 C7 C10 C11).
By doing this you are allowing lower harmonics to go into the circuit, the standard combination 100K resistor with 100nF cap attenuates values below 15Hz.
Using a 470nF, the whole deep spectrum down to 3Hz can go into the circuit.
By saying that 15Hz is pretty low, but if you want to experiment or you have some caps around you can try.
Any radial, through hole, ceramic capacitor between 470nF, 510nF 680nF with a voltage of 16V or higher will work. (Take care, if the voltage is too high, like 500V or so, they can be bulky and difficult to fit)
Can the 50k resistor (R7 - actually 49.9k) be replaced with some other value?
I'm having some trouble finding those locally.
R7 value is the equivalent of R8 in parallel with R6 (100K//100K=50K) this resistor is used to equalize the offset currents and avoid having voltage offset at the output of the op-amp.
Since we are using a JFET op-amp (TL072) this offset currents are very low so you can build the pedal without this resistor:
Place any resistor from 0ohms (a wire shorting the pads) to 50K and it will work.
The administrator has disabled public write access.