Krell KBL Static in Right Channel

Hi all,

Recently picked up a Krell KBL as-is from a garage sale. Everything was sealed in the box but there were some scuffs on the preamp, so I assumed it was sent to Krell for repairs/recapping and then sent back to the owner. Apparently the box sat unopened in the previous owner's garage for a decade or more.

After hooking up KBL, the sound is excellent. More powerful bass and better soundstaging than what I remember from my previous KBL. No channel imbalances or imaging problems from what I can tell.

However, there is a strong static sound coming from the right channel of the KBL which sounds like TV static through my right tweeter. It's not terribly noticeable from the listening position but it's indelibly loud 3-4" from the tweeter. Left channel is dead quiet. The static doesn't change in loudness when I adjust the volume knob of the KBL. I'm sure it's coming from the KBL and not my amp because the static switches to my left speaker when I reverse the main out cables on the KBL.

Any ideas what this might be? Improper grounding? Broken capacitor? I'm a bit confused because everything else sounds top-notch except for the addition of this static on the right channel. For reference the KBL is connected via balanced XLR cables to a Mark Levinson 23.5 amp.

Thank you!