>>>The later 3 volt PS2 boards accommodate 2 Meg sound files. However, the older 3 volt PS2 boards will allow on 1 Meg files.<<<
Thanks - I realize this now but my point is, the MTH Protosound website list them all as 3V, not by size.
Maybe I can go by catalog date. Do you know when the 2mb 3v boards replaced the 1mb boards in production?