Azymuth and mis-aligned carts can.
Marakanetz is correct that either can be an issue. Have you tried other sources such as CD or tuner to see if the problem is specific to the vinyl front end? In vinyl, have you listened to a range of records to isoloate perhaps a bad recording or three? Did this happen all at once, gradually, or come about after a change in components or component placement, especially speaker placement or placement/addition/removal of other large objects in the room?
On a side note with respect to azimuth, a few of us recently purchased a Wally azimuth tool and I found that, after testing, my Graham 2.2 was stunningly spot-on eletronically speaking. Then, as a lark, I adjusted the azimuth both ways beyond the tolerances that Wally suggest as tolerable. The most immediate impression invloved a shift in the soundstage from left to right and vice versa. Luckily, my Graham is very easily adjusted for azimuth. This might not be so easy to test with other arms.
What we hear when antiskating is off is a loss of focus or cleanliness on one channel or the other, no doubt caused by the stylus' inability to trace one groove wall accurately. Images do not really shift sideways, it's just that one side is clearer than the other.
Thanks to the same Wally tool mentioned by 4yanx I know my cartridge is:
a) stronger on the L channel by one click on my preamp's balance control and,
b) significantly off-azimuth internally, resulting in 8-9db of crosstalk between channels.
So if you wanted to know what a channel-imbalanced, seriously off-azimuth cartridge sounds like when antiskating is mis-set, well, now you do!
Divo, if you have the Graham (I have a 2.2), use a small bubble level and place it across the front of your head shell to set your azimuth initally. If the head shell is level based on this, it should be close enough that you don't have the imbalance problem. You can fine tune it from there if you want. If you do this and still have the problem, I would suspect a defective cartridge or something else in the system chain. Are you sure you haven't moved the right speaker forward a couple-o-inches? :-)
Hi Divo: You have to check every single parameter in the
tonearm/cartridge operation : Azimuth, VTA/SRA, VTF and antiskating, sometimes the sum (+) of little deviation from all these adjustement comes with a problem like you have, be sure the stylus is clean and "see" if the cantilever is right at the center of the cartridge.BTW, how many hours has your Ruby?.
Some day with one of my cartridges I have your problem and after to check all those adjustement the problem still exist, that time the problem was: a loose conection between the wires in the headshel with the pins ( dirty pin ) in the cartridge and a " weak " conection between the DIN 5 pin conector of the tonearm cable and the tonearm pins.
You have to check all these.
Regards and enjoy the music.