Clearly determined to provide an early source of pleasure (7,3)
I believe the answer is:
crystal set
'provide an early source of pleasure' is the definition.
I can't judge whether this definition defines the answer.
'clearly determined' is the wordplay.
'clearly' becomes 'crystal' (I can't justify this - if you can you should believe this answer much more).
'determined' becomes 'set' (synonyms).
'crystal'+'set'='CRYSTAL SET'
'to' acts as a link.
Can you help me to learn more?
(Other definitions for crystal set that I've seen before include "matching items of glassware?" , "used to receive long ago" , "Receiver" , "Matching glasses" , "Radio" .)