Repair diagnosis for cdp with humming tranny

Newbee,

I would lift the PC boards the transformer is attached to (INPUT and OUTPUT) and check ALL solder joints, but especially under capacitors and rectifiers and under wire connections. Chinese made gear often exhibits poor solder, especially in higher current areas like power supplies and power amp outputs.

Thanks for the advice. Unfortunately nothing works, really. 

Elizabeth, FYI as you like using spinners and DAC's. I tried using the digital output of the Raysonic into the Marantz (SA11s3) input - didn't care for the sound at all. But, I acquired two other cheap DACs, the Cambridge and the Peachtree. The Cambridge was OK but it really worked better with some cheap spinners I have. The Peachtree was an improvement over the built in DAC in the Raysonic. Clear, clean, linear, and tonally spot on. Great synergy with my system. FWIW.

Over time, the transformer core adhesive starts to break apart, maybe some large heavy duty hose clamps could help.
https://www.qsl.net/kf8od/ccore11.jpg
https://www.qsl.net/kf8od/ccore7.jpg

Try it in another home. 

If it goes away, you have DC on your line. 

The cure for this is to eliminate the source (often digital power supplies, and dimmers) or to get a balanced power supply. 

Best,

E

Just teach him the lyrics.

Raysonic is long out of business and doubtful there are any parts available for them.  Perhaps check ebay?