Marantz eq 315 cause speaker hum


Hi all, looking for guidance here.

Everytime I switch on the EQ button on the equaliser I get a 60hz hum. When I switch off the EQ it stops. The EQ has a 2 pin power cord so not sure if ghat has anything to do with it. I really like the EQ so want to check what might be causing it. Would balanced to RCA cables help?

Please advise.
rohanraman