Wierd Phono problem - what causes this?

Flip flop your tubes left and right..Maybe a tube???

I'll bet your right and left channel + & -'s are reversed in some fashion at the cartridge.

Is the cartridge mounted correctly?

I had a very similar problem,which took alot of time to diagnose.In my case,it turned out to be a phonostage problem,which is being fixed,as we speak.This sounds like your situation.

The actual reason for my own problem,was something that could have easily been avoided,if I had a dealer(who sold me the "reason" for the "issue"....a long story)who cared about a customer's satisfaction,beyond the quick profit being obtained.

Much aggravation later,and I am on the cusp of getting back to where I belong.

I hope you can diagnose the problem without too much angst!

Good luck

Thanks for your responses, all. I just gopt through playing around with it, and it seems to be a phono stage problem. Switching R & L cab;es coming from the record player into the phono stage didnt change anything, but switching the phono stage output cables at the phono stage caused the problem to change channels - now R side is bright and aggressive. I switched the tubes, but this didn't seem to have any effect. Ths condition is the high frequencies are a lot louder in the L channel than the right - panning the balance control right to left, the right channel sounds pretty good, but the high frequencies get a lot louder panning side to side, so it doesn't sound like the lows are getting attenuated. I think I'm goiong to write to the manufacturer.