Hi,
i believe all E88CC/6922/CV2492/CV2493 were made at Mitcham factory (code R). Blackburn (code B) made ECC88, though having the Master facility as well. I never traced a Blackburn made E88CC even to back 1961 made ones, if ever made at that factory is very rare and prior 1960.
Mitcham ones after 70 have different construction and sound different.
i believe all E88CC/6922/CV2492/CV2493 were made at Mitcham factory (code R). Blackburn (code B) made ECC88, though having the Master facility as well. I never traced a Blackburn made E88CC even to back 1961 made ones, if ever made at that factory is very rare and prior 1960.
Mitcham ones after 70 have different construction and sound different.