great to see you come along on this project.
the best way to put together without crosstalk would be to use both op amps on the chip on the same channel and take a .01-.1 uf at 50v or whatever ceramic cap from each vcc pin to ground as close to the vcc ic pin. do this on all op amps. this will prevent the negative feedback from being injected into the Vcc's "ac ground" .
on some op amps this phenomenon is caused by the impedance of the power not lower than the feedback loop. this is caused by low Vcc and using a split rail op amp in a single supply circuit. refer to the specifications of the op amp being used. the two 10K's that make the voltage divider network for the 100k bias feed resistor in the front could be eliminated if the op amp's operating voltage supply was higher. 15-17.5V for 18-20V op amps and 18.5-20.5V for 22-24V op amps is what I recommend. most of those op amps that are operated below 15V require bias compensation and from my experience, compromises the performance. refer to the op amp's data sheet for proper operation.
the potentiometers lead wire should be paired together. twisting the pair going to the potentiometer might help. also the wires could be changed to some nicer shielded cable if shielding the cable the shield can either be tack solder directly to the potentiometer and grounded, left floating but grounded electrically, or shield to potentiometer thru a .01-.1 cap and the other end grounded.
the best way to put together without crosstalk would be to use both op amps on the chip on the same channel and take a .01-.1 uf at 50v or whatever ceramic cap from each vcc pin to ground as close to the vcc ic pin. do this on all op amps. this will prevent the negative feedback from being injected into the Vcc's "ac ground" .
on some op amps this phenomenon is caused by the impedance of the power not lower than the feedback loop. this is caused by low Vcc and using a split rail op amp in a single supply circuit. refer to the specifications of the op amp being used. the two 10K's that make the voltage divider network for the 100k bias feed resistor in the front could be eliminated if the op amp's operating voltage supply was higher. 15-17.5V for 18-20V op amps and 18.5-20.5V for 22-24V op amps is what I recommend. most of those op amps that are operated below 15V require bias compensation and from my experience, compromises the performance. refer to the op amp's data sheet for proper operation.
the potentiometers lead wire should be paired together. twisting the pair going to the potentiometer might help. also the wires could be changed to some nicer shielded cable if shielding the cable the shield can either be tack solder directly to the potentiometer and grounded, left floating but grounded electrically, or shield to potentiometer thru a .01-.1 cap and the other end grounded.