I know this Thread is about the FR-66s, but the FR-64s was introduced into the discussion and because its geometry is different to that of the FR-66s......I feel it needs some elaboration:-
Recommended for FR64s: 231.5 mm P2S, 14.5 mm overhang and 20.5° off-set angle.
This will give a very good tangential curve with very low maximum as well as very low average distortion figures in the last 2/3 of the record. For the last 66% of the groove this tangential curve outperforms Baerwald and Loefgren in any version by a very good margin.
With this geometry, the FR64s' tangential curve becomes very similar to the FR66s' original tangential curve.
This tangential curve honors the FR64s' original geometry - i.e. there is no additional breakdown-torque implied.
Recommended for FR64s: 231.5 mm P2S, 14.5 mm overhang and 20.5° off-set angle.
This will give a very good tangential curve with very low maximum as well as very low average distortion figures in the last 2/3 of the record. For the last 66% of the groove this tangential curve outperforms Baerwald and Loefgren in any version by a very good margin.
With this geometry, the FR64s' tangential curve becomes very similar to the FR66s' original tangential curve.
This tangential curve honors the FR64s' original geometry - i.e. there is no additional breakdown-torque implied.