Long RCA interconnects

I recommend Blue Jeans cable LC-1. Shielded. Low capacitance. Affordable. I have several long runs. No loss of highs. No hum. No noise of any kind. Money back guarantee. 

Try running the AC lines from the same spot as the pre or amp, to reduce potential for hum. Ie, the same ground potential would be the result of the AC is from the same exact receptacle.

If you get some hum, try the ’same AC origin point’ trick. Play with the AC to try and reduce hum, is the deal.

We've made 6.5-7M RCA cables for people -- totally unshielded btw. No hum. That's a $35k pair of cables. Better hope there's no hum.....

Wow that’s a low gain phono stage (42dB/57dB) - so you could be in for some issues if you’re driving a long run off it. The stage itself is capable of driving a healthy 2-20V output but it would be good to know what’s coming in, what cartridge do you have? Hopefully MM or high output MC

I have a Benz Micro Silver MC

OK that's a healthy 2mV output so the phono stage will be outputting 1.4V which is a good signal and should put you in as good a situation as you could hope to drive that long single ended run. If you had a .3mV output (i.e. typical low output MC) things might be more problematic -- anyway good luck!