Buffet Crampon S1 clarinet

MRO Saxophones performed a series of Buffet Crampon clarinet overhauls and maintenance checks early 2022, including two S1 models. The S1 is a rather uncommon version and not that many were made during the 1970´s. The first one is an early one from 1974, and the second one is a late one from 1980. I notices some important differences between these S1 clarinets, and couldn´t find any info online on these differences. Both clarinets have the ´F´-prefix and were made for the European market.

Clarinet A : Buffet Crampon S1, serial F145204 (early 1974)
Clarinet B : Buffet Crampon S1, serial F206107 (mid 1980)

1) The bore is different. Clarinet A has a bore of 19.90 - 14.50 mm : clarinet B has a bore of 14.85 - 14.65 mm. 

2) The barrel is different. Clarinet A barrel is 63.6 mm : clarinet B barrel is 65.0 mm (both barrels are original).

3) Very interesting : clarinet A has the cut-out below the right hand pinky plateau (as all R13 clarinets have) but clarinet B doesn´t have this cut-out. Strange....

For the record : both clarinets were tested by a professional (classical) player and by myself. We both agreed clarinet B is a bit easier to play but clarinet A is a bit more focussed. We also compared both clarinets to a standard R13 clarinet from 1985: the difference in sound was marginal.