Terence:
Interestingly I have read that the Decca phase 4 records are preferred to the London pressings for sound quality.
When I have spoken to DECCA about this, John Dunkerly is one source, they were adamant that London and DECCA pressings were all done in England thus exactly the same.
In rare cases a master tape copy was used for a foreign release but in most cases pressing stampers were sent if there was a need for a swift release.
I have compared the matrix numbers on many London releases with their DECCA releases and they are the same so far after more than a few hundred comparisons so far during some 35 years of listening and looking and I cannot hear any difference.
The reason given for doing it this way was for keeping the quality up.
DECCA always used the original edited master tape as the source for the Neumann cutter as they felt that the quality loss from using a copy tape was not acceptable at all to them.
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Best regards,
Goran Finnberg The Mastering Room AB Goteborg Sweden
E-mail: mastering@xxxxxxxxx
Learn from the mistakes of others, you can never live long enough to make them all yourself. - John Luther