Is it ground loop problem ?
I have a outdoor ant fed into my tuner tu-9900 then ARC ls-3 (known
for being sensitive to ground loop). There is noticeable humming no
matter I play tuner or other source but disappears if I disconnect the
ant input. I did ground the antenna using a grounding block, the
problem is improved but still there.
Any help/comment is appreciated ! Thans!