My Oppo hums

Likely the hum is not caused by either, but is the product of an ungrounded cable or sat system. Unplug the cable (COAX at the wall) and see if it goes away.

All of the Oppos so far have had no ground pin at all, so even if your cable is grounded you will not be running a grounded connection. I'm pretty sure that lack of grounding can pass through the SPDIF connection to your DAC - but someone with more knowledge on this should confirm. I know the power supply on the Oppo is definitely not its strong suit. I heard through the grapevine that they were making a concerted effort to improve on the power delivery (not sure when that may become implemented). I don't know whether this includes a standard grounded IEC connector or not. I think lack of a ground is continued with the 93, but wonder if it will be improved upon with the 95?

Actually the Burson PI-160 is an integrated: sorry I didn't mention it as such. But I see your point as it wouldn't matter if it were a DAC or integrated. I'll try what you suggest later this evening.
Thanks.

Oppo has excellent customer service, IME. Call or email them.

Hum is not transferred through digital connections.

Does the Burson PI-160 use the equipment ground, third wire? If so you may have a ground loop problem.

If you have a CATV or SAT cable system and it is connected to the audio system in anyway then the hum could be ground loop related....

For a test disconnect the CATV or SAT coax cable from the system. Check for hum. No hum buy a CATV cable ground isolator. Jensen makes a good ground isolator.

The Jensen will not work on a SAT system.