First, make sure all alignment and setup parameters are correct, including VTF and azimuth as well as overhang/zenith. A slight inaccuracy in azimuth could cause this problem.
If that doesn't help then the JMW-9's rudimentary antiskate "adjustment" becomes a prime suspect. If inaccurate antiskating is to blame then left channel sibilance indicates a need for LESS antiskating force. Try unplugging your wire, allowing it to return to a neutral position and start from there. Increase twists one at a time. Make sure the wire is dressed so that it puts no sideways pressure on the arm anywhere across its arc.
If no happy medium can be found between too few twists and too many, you might consider buying the optional antiskate mechanism VPI now offers for your arm. I've read good reports about it.
BTW, what cartridge are you using? Some are better than others at tracking difficult inner grooves.
If that doesn't help then the JMW-9's rudimentary antiskate "adjustment" becomes a prime suspect. If inaccurate antiskating is to blame then left channel sibilance indicates a need for LESS antiskating force. Try unplugging your wire, allowing it to return to a neutral position and start from there. Increase twists one at a time. Make sure the wire is dressed so that it puts no sideways pressure on the arm anywhere across its arc.
If no happy medium can be found between too few twists and too many, you might consider buying the optional antiskate mechanism VPI now offers for your arm. I've read good reports about it.
BTW, what cartridge are you using? Some are better than others at tracking difficult inner grooves.