Hello, I recently built Eddy Bergmans Steiner Parker filter and am having some issues. I haven’t added cv ins or outs yet, so just input output and the filter select switch. I am dealing with a ground hum/buzz sound on the output of the filter. I have checked grounds a million times and everywhere ground should be, it is. What components could cause this phenomena ? I really want to learn these things to make diagnosing less of a literal nightmare.
I have attached a video of the sound in question. emphasized texthttps://youtube.com/shorts/jBNWxGNO8Dw?si=hZ0oIFz9KwHQvsec