[78-L] Equalisation question - UK Columbia

[Andrew Evans]

Can any of you learned gentlemen (and ladies, of course, no less learned)
suggest approximate dates when European Columbia switched from Westrex to
Blumlein processes, with the corresponding changes in Eq curves? Dates for
Abbey Road and Paris would be particularly helpful, but I'm sure other
readers might appreciate any available information on the re-equipping of
other studios.

Supplementary question: might there any correlation between the switch and
the change in Mx numbers from (W)L #### to CL ####, which seems to have
taken place some time around the turn of 1932-33?

Andrew in Luxembourg