[78-L] Vox question

[David Lennick]

This past week I found a Jacob Gimpel Chopin recital, Vox album 604. Presumably 
recorded in Los Angeles since the cutting style is Radio Recorders and the 
pressings are like Capitols, but the matrix numbers are in a series I'm 
unfamiliar with: IMS 7001 through 7008. (Radio Recorders' own hand-scratched 
numbers also appear, A-2262/9.) The IMS numbers are in a similar font to other 
RR masters of the mid 40s..anyone know what the letters stand for?

dl