Fair warning, I have no useful knowledge in electronics besides practical applications learned in practice.
I have 3 circuits in one enclosure. Drive, filter, and clean boost. All on different boards. When I turn on the clean boost, it's inversely affected by the drive circuits gain. Aka, the more gain I add, the less gain the clean boost puts out.
I assume this has to do with ground issues. It's there a way to isolate the ground between the different circuits? Or some other super dumb thing I could be doing. All circuits test fine on their own.