Channel imbalance with turntable playback

Yes if you swap one cable, left goes to right and right goes to left, but if you switch two sets of cables. you are back to the proper side but using the opposite side of the amp or preamp. There are no rules for using the left side channel of an amp to run the right side signal to the right hand speaker.

Not sure what are you trying to explain to me. Are you aware of phasing, absolute polarity and channel orientation? We must listen music just like it was recorded, if you play music in the iPhone (it has two speaker now) you can rotate the iPhone 180 degree (for example), but only one position is right (true to the source) in stereo recording. If the OP prefer to listen his system virtually rotated 180 degree that’s not right!

There is a right and left speaker in the mastering studio when musicians recorded, left is always left and right is always right. Same on the cutting head. You must listen to the stereo sound exactly how it was recorded (picket up by the microphones in the studio). You can’t change position of the musicians, if you will do that by swapping L and R channel cable you will ruin everything. You can swap disconnected L and R speakers - it doesn't matter, but if you swap connected speaker then you must swap cable ends on the amp terminals too. 

@paulgardner,

So I’ve been having a slight channel imbalance for awhile now.

If your phono stage has tubes start the checking from there, if not try to realign your cartridge.

visual check azimuth  . if your using headshell there is a slight slack that you can manipulate 

learn to properly set antiskate.in general too much antiskate left becomes thin. in general our daily LP are only using 30 to 40 percent modulation. thus.. it's also more correct to set only about that much anti skate. 30 percent of the total vtf. test LP have more modulation.. thus.... easily get confused. 

read up peter of soundsmith article and YouTube. his info is spot on. 

@chakster I believe @russ69  is talking about phase inversion. If done in even numbers it balances out
IE Conrad Johnson preamps are phase inverted. To get back to phase, you invert the phase at the speakers, R to L & L to R. CJ covers it nicely in their manual.

If you want to get to the root of the problem then probably best to follow the suggestions for anti-skate and cartridge setup first. If you don't mind the reversal of left / right channels then that's fine and will result in no other undesirable artefacts.

The bit I don't get is that swapping L/R channels results in a better balance, you'd think it would just be out of balance in reverse.

Are you aware of phasing, absolute polarity and channel orientation?

In order to change the phase you'd need to reverse the connections at one end of the RCA connector... I don't think anyone suggested that. Polarity is just phase referenced around 180˚ steps, so that won't be a problem either. Channel orientation will of course be affected (unless the outputs of the pre are swapped as per @russ69's suggestion).

Final thing... is it just your TT that sounds out of balance? Left/Right tracking on potentiometers is pretty poor and changes with the volume setting so if other sources are out of balance and you have a potentiometer for a volume control it might be worth checking that as well.