@roxy1927 So happy to read that you have largely solved the problem! I, also, much prefer good clean vinyl over digital and would be hard pressed to give that up.
I have no idea if this will help in any way. However, I also was perplexed by a slight hum in my two-channel system incorporating a TT and integrated amp. The hum could only be heard at high gain using the TT and was completely absent when using a CD player. I rearranged all my components on my rack such that the amp (i.e. its power supply) was located as far away from the TT as possible (i.e. approximately 3 feet). That did not resolve the problem. This was ultimately resolved quite by accident when I cancelled my DIRECTV subscription and got rid of the two DIRECTV satellite receivers that I had placed on my rack. The hum issue totally disappeared, even at high gain levels. I have an LG flatscreen right behind the stereo rack. So, seems clear to me that the problem was related to the DIRECTV satellite receivers. Maybe cable TV external boxes or receivers present the same problems? No clue.

