just pointing out that al the discussion of new fanged digital misses the point. The TRS to RCA cable and the connection is analog. The noise is ground noise. No digital involved.
FInally I have a noise issue
Got a 5M 1/8” (3mm) headphone jack to RCA lead.
When the sound is not playing on the iPad it has low buzz coming out of the speakers.
And I’ve almost convinced myself it is picking up RF.
Other PreAmp inputs are mouse quiet.
Should I wind a copper wire around the thing and attach it to the preamp ground as a test?
Or I suppose a properly shielded cable is what is used??