Lyra Lydian Beta, Rega hum?

This rig is all new. Bought the cartridge from overseas seller. Last night I shut my amp off and listened with headphones through my Sonic Frontiers line 2SE headphone jack. There is a hum in stereo, but when I switch to mono the hum is at such a low level it is not a problem. Why would it hum in stereo and not in mono? When I use mono through amp and speakers hum is lower than stereo, but not really tolerable.

Problem solved! Had a repair guy check it out and he found the pins on the cartridge were labeld wrong! Never would have found it myself.

WOW!! Who woulda thunk it?!? Thanks for the update- I was wondering how this would turn out...

Regards
Jim

...and that's what I've told on my first post here...