I have revised the 822 schematic changing part values for VR18, VR19, R30 and R31.
These are not required changes to your 822. If you have it built and it calibrated fine,
do not go back and change your 822. However, in building and calibrating several 822
modules, I was not able to match the B channel perfectly with the A channel due to
variations in part tolerances. These new part values accomplish two things:
1 – more adjustment latitude in matching the channels.
2 – fewer matched parts are required (reduced from 12 to 8)

So, if your 822 calibrated to specifications, you have nothing to gain making these changes. If you have not built it yet, I do recommend the revised version. I am leaving both versions of the schematic on line: