Actually the cassettes were just the same, but I never tried the 1531 on a C64, don't know if it will work, have to look at the pin allocation of the cables. I only got the 1531 later, when I didn't use the C64 anymore (daily).I never knew the cassettes were 1530-1531,s just cassettes.
Guess that won't workHave you ever toyed with saveing data from a 500 or what ever on these.
I guess you can easily find one on any auction site.Bet there not for sale.