listening to drum beats on a slowed-down cassette player

[http://dummy.us.eu.org/robert (Robert)]

I think I remember years ago that you told me that you had a way to slow
down tapes so that you could figure out drum beat patterns.  Am I
remembering that right?  If so, did you do something like?:

 http://ofsoundmind.wordpress.com/2008/01/24/primer-pitch-bending-a-walkman/

Or, did you buy a player with this capability?

(I know this is old skool since it's easy to do this with
digitally-encoded audio and computer software these days.)