Electromagnetic interference

Just bought a Conrad Johnson classic 2 preamp. Getting 60 cycle hum through speakers. Instructions say put the preamp well away from the amp. How far would that need to be?
0bef2367 cae5 45e8 a425 e7237cfbc40bheterodon

There are many reasons a 60 cycle hum can occur in a system. More info about your system would be necessary to determine the issue. How far apart is the preamp and amp now? 2-3 feet?

The amp and preamp are separated by one shelf up and down. About 4 or 5 inches!
It's very simple to move the preamp away and observe the effect. As Nike says,just do it. That's your 1st step.