Topic: Why crosstalk from playback to analog mic input?
I am using UCX(along with several more rme products). I recently noticed there was a strange crosstalk.
I use phantom power to trs plug-in power(5v bias) adaptors, for example, VXLR+ and D-XLR.
Both work fine but there is some crosstalk. If I connect the adaptors to the analog xlr input 1 and connect nothing to their trs jack(hence no input), and play any sound from computer through playback 1/2 and to a headphone output, the playback sound bleeds into the analogue mic input. The analogue mic input gain is at 33db and noise floor is at around -85dbfs(peak) but when music is playing the noise floor suddenly jumps into -50dbfs. It's 35db's difference and it's huge, I think. This doesn't seem to happen when an xlr cable is connected to the same input without connecting it into anything.
Why would this happen and what can I do to lower the noise floor when using such an adaptor?