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The biggest culprit is plugging your modular synth into one outlet and having your recording system (computer and audio interface) plugged into a different outlet. If you can get both parts plugged into the same outlet that might be helpful for reducing or eliminating that ground hum. That would be the first thing I'd try to fix.

Next would be removing all the modules except for case power. Then add one module at a time or two or three. Power up the case and see if there's an issue with noise. You may have an inherently noisy module (digital modules with displays can do this). Or maybe a module that has failed in some way. It's good to rule out a bad module.