As first step switching the source circuit is worth a try and easy to do. That said, household wiring is not as isolated as you might think even if you are on another circuit. Try an separate between odd and even circuit numbers. There are two potential issues each with different solutions. The compressor is most likely producing electrical noise which is being carried through the wiring to Millzebub. If this is the case you will need to add filtering to the power wiring such as a the suggested line conditioner. FYI, switching circuits might work as the electrical wires them self can act like a filter if long enough. As barry90705 said "Distance!" The second less likely possibility is that the compressor electrical noise is begin broadcast through the air, in which case you will want to shield from this RF noise. The simplest solution again is distance. When distance is no possible then you will need to add shielding. Typically you would add a shield around the sensitive equipment i.e. Millzebub's controller, computer, and cables. Guessing from you cable assembly pictures, your cables are not shielded, thus they can act as antenna and pick up the RF noise. Before you go to the effort and expense of replacing your cables with shielded ones and adding a shield around the control equipment, first test to to see if this is a problem. If possible completely enclose the compressor with grounded metal. If not possible try to cover just the motor, or create a wall or sheet of grounded metal between the compressor and Millzebub. If you are able to cover the equipment ensure that there is an air gap so you don't over heat the equipment.