I have two Marantz receivers, SR8000 and SR7000. Plugged in headphones into phones input on my primary 4+ years old receiver (SR8000) for the first time today. The problem is, I only get left channel in the headphones. Tried the same headphones with the same connector on SR7000 upstairs and it worked fine. Both receivers are very similarly built and looking. SR8000 simply has more power and few more features. Is there anything I can do to fix the problem? If it were a faulty phones input, would it make sense try to get it fixed? I, of course, could swap two receivers but I purposely bought a more powerful unit to drive a larger sub and four floor standing speakers. I'd appreciate *any* suggestions. Thank you.