First of all, we have had access and used the original mastertapes, recorded by André Charlin in 1956 & 1957.
The full analog mastering of this edition has been done at Trutone Mastering Labs in New York, by Carl Rowatti ; having more than 40 years experience behind him, Mr Rowatti is renowned as an « artist «  of cutting and mastering vinyl records.
The cutting system used for that work includes :
– A specific Studer A-80 pre listen tape machine, with 2 heads, specially designed to provide the necessary analog tape delay required for the lathe’s computer to adjust the groove spacing and depth without converting to digital and back to analog to achieve the required delay. The whole process remains 100% pure analog.
– to the Neumann SP 77 console and the Neumann SAL 74B cutting amps, have been added an extremely rare vintage Fairchild 670 vacuum tube compressor from 1957, and an as rare Pultec EMH7 vacuum tube equalizer ( there are only 3 other existing copys in the world ! ).
The cutterhead is a Neumann SX 74.
vacuum
vacuum tube Fairchild compressor 670
vacuum tube Pultec equalizer EMH 7
We have proceeded carefully, wisely, in full respect of the original tapes, avoiding any unnecessary adjustments, in order to reproduice and preserve faithfully the artist’s performance.

Watch an hilight of the process here :