Cassette player perhaps found next to class pigeonhole (10)
I believe the answer is:
stereotype
'pigeonhole' is the definition.
(to pigeonhole is to stereotype)
'cassette player perhaps found next to class' is the wordplay.
'cassette player perhaps' becomes 'stereo' (personal stereo).
'found next to' is a charade indicator (letters next to each other).
'class' becomes 'type' (I've seen this before).
'stereo'+'type'='STEREOTYPE'
(Other definitions for stereotype that I've seen before include "Conventional image" , "cast" , "received idea?" , "Fixed conventionalised image" , "Spring back (in fear)" .)