Dear Axelwahl, good to learn your mounting distance is fine. If you had checked that earlier, we could have spared some time and space here...
Anyway - if you still have inner groove distortion when the tonearm geometry itself is fine, then this can be related to several points:
a) lateral azimuth of the cartridge/stylus
b) horizontal azimuth of the cartridge/stylus
c) antiskating
d) 2nd zero-error point already long passed when you reached the inner grooves (the SME uses an IEC-standard when calculating the zero-error-points. The 2nd point is pretty close to the 1st and in the inner grooves you are close to the maximum error - why this IEC-standard was used and favoured by SME and Ortofon was explained in the "Prices for Oldskool tonearms"-thread. It has to do with the new way to master and cut LPs in the early 1980ies.
a) and b) can hardly be altered in the SME V, but you can try - usually there is a small degree of free movement. Both do have direct impact of the position of the stylus contact area to the groove walls.
c) antiskating or skating force as the source of distortion will apply, when the distortion is pre-dominant in one channel only.
Anyway - if you still have inner groove distortion when the tonearm geometry itself is fine, then this can be related to several points:
a) lateral azimuth of the cartridge/stylus
b) horizontal azimuth of the cartridge/stylus
c) antiskating
d) 2nd zero-error point already long passed when you reached the inner grooves (the SME uses an IEC-standard when calculating the zero-error-points. The 2nd point is pretty close to the 1st and in the inner grooves you are close to the maximum error - why this IEC-standard was used and favoured by SME and Ortofon was explained in the "Prices for Oldskool tonearms"-thread. It has to do with the new way to master and cut LPs in the early 1980ies.
a) and b) can hardly be altered in the SME V, but you can try - usually there is a small degree of free movement. Both do have direct impact of the position of the stylus contact area to the groove walls.
c) antiskating or skating force as the source of distortion will apply, when the distortion is pre-dominant in one channel only.