Recording put in class (8)
I believe the answer is:
cassette
'recording' is the definition.
(I've seen this before)
'put in class' is the wordplay.
'put' becomes 'set' (both can mean to place or position).
'in' is an insertion indicator.
'class' becomes 'caste' (type of social class).
'set' going into 'caste' is 'CASSETTE'.
(Other definitions for cassette that I've seen before include "sealed plastic container" , "bit of outdated technology?" , "Recorder would accommodate this" , "It may contain film" , "sound equipment" .)