How far is your SUT from your Phono Pre/Preamp?

Mine is inside. I am assuming that your’s WAS external?

I think I get it. He was using an external SUT instead of the one built into his phono pre-amp but switched back because he was getting hum.

Usually hum is from cables that are not properly shielded, ground issues, things like that. I run a Denon AU-340 SUT with 3' cables going into my Audio Research SP8 that sits about 10" from the SUT. No issues what ever. I have all my grounds attached to the back of my SUT, the ground from the SP8 and the ground from the tonearm cable.

BillWojo

The short answer is no, you need not tolerate hum just because your SUT is close to your phono stage. In fact ideally you want the two to be as close together as practical.

External SUT should be hum free -

Use low capacitance shielded cable between SUT/phono

Make sure SUT chassis is earthed to phono via additional earth wire

Should be close as possible. Above comments correct, use a good phono cable to connect to pre...hum can be reduced greatly by turning the sut....if you cannot hear hum at listening position, then there is No problem.