Thanks for all the advices. This amp weighs 110 lbs with box so want to go over all possibilities before I take it in. For now, I think I can live with it given I have 2 more years of warranty and can take it in if it gets worse.
I don't think it's interconnect since it happens in all channels and don't think it's tubes since 2 sets (1 old 1 new) have same issues. Might be a bad socket or capacitor or fuse. Is McIntosh MA2275 easy to open up to check for capacitor or fuse? Thanks.