Bugsnest, I don’t think power conditioners help DC in your lines, they may but it didn’t help me.
I have a Running Springs Dmitri, Hayley and PI Audio Uberbuss and tried them all when I had a mechanical transformer hum on a Conrad Johnson amp. I had to send amp in for a replacement in 30 day period. The new amp had no hum so my problem may not have been DC in my line.
If you have DC in your line you can try a Van Alstine Humdinger DC line blocker $140. That was next move if new amp still had hum.