My first suspicion is a ground loop, and they can be difficult to locate and fix. I'm assuming the audio and HV are on separate PC boards, so the solution is with cabling and perhaps a filter in the right location. It's possible an oscilloscope can help, but be aware that the ground-lead to your scope can add to the noise you see; there are several good techniques posted on the web.
When I built my first computer, the ground loops were SO bad that I could hear interference on an AM radio several houses away. It was amazing how easily I could trace the wiring inside the walls, because of the noise. After I removed the power-supply ground loops, there was no detectable noise outside the computer cabinet. -- You received this message because you are subscribed to the Google Groups "neonixie-l" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To post to this group, send an email to [email protected]. To view this discussion on the web, visit https://groups.google.com/d/msgid/neonixie-l/ce7437fe-a1d6-4a1f-8a70-e73626ead8e5%40googlegroups.com. For more options, visit https://groups.google.com/d/optout.
