Oakley Sound
DSCF5612
Added 68nF capacitors in parallel with feedback resistors to reduce the amplitude of LFOs at higher frequencies. This gives a more constant modulation depth as the LFO frequency is increased.
I removed the two 10uF capacitors on the audio output lines. You can see four holes near the output sockets where they were. I then added 470R series resistors (not seen in this photo) to the output of the final op-amps. Although this does increase output offset slightly it is still below 10mV. The resistors prevent the output op-amp from oscillating with cable capacitance. Remember I have no HPF stage on my unit and the output of the summing amplifier goes straight to the relay.
DSCF5612
Added 68nF capacitors in parallel with feedback resistors to reduce the amplitude of LFOs at higher frequencies. This gives a more constant modulation depth as the LFO frequency is increased.
I removed the two 10uF capacitors on the audio output lines. You can see four holes near the output sockets where they were. I then added 470R series resistors (not seen in this photo) to the output of the final op-amps. Although this does increase output offset slightly it is still below 10mV. The resistors prevent the output op-amp from oscillating with cable capacitance. Remember I have no HPF stage on my unit and the output of the summing amplifier goes straight to the relay.