Unplug your cdp inputs, plug in Headphones and turn on unit. See if hum level has changed.  If so, then perhaps a ground loop issue.  Location of your mlb or other tube gear for that matter next to other magnetic fields could induce noise as well.  Try it in a different location, on a different circuit, etc.  did you swap the rectifier?

I have a csp2, but my cd is actually a dvd player that when connected to my tv, induces minor hum on the system.  Usually I don't care until I want to listen to headphones which tell all, so I then unplug the video.

Matt

Back to the factory it goes for a good once over. It was packaged and sent out this afternoon. I can hardly wait until its speedy return!

How lonely its MDF stand looks. When the unit returns I will be making a stand for it using that platform and some moulding on the sides, then painting it black.

I began using the amp at my office and for some reason I do not notice any bothersome hum. Go figure.