CS4397 dac

[Bodran]

Need some basic help. First let me state that my background is in mechanical engineering rather than electrical but I do like a challenge.
So far I’m using this dac stock with the supplied power supply. I was happy that it worked at all after I hooked it up. First problem I noticed was it is louder in one channel and I have to use the balance control on my preamp (lucky I even have one). So I have been looking here for a solution.
Could the different values of R8, 9, 14 & 17 cause this?
Later on I read about that someone had a bad voltage regulator, I figured that is easy to check so I did and the +5 volts is +5.1v the +12v is +11.81 but the -12v is -16.44v. Looks like a problem on the -12v to me but is it causing the channel imbalance? I measured at the first power supply connector relative to the AG pin.
Regards.