At the piano, he'd get the melody right (5)
I believe the answer is:
tuner
'at the piano he'd' is the definition.
The answer is a person as well as being a singular noun. This is suggested by the definition.
'get the melody right' is the wordplay.
'get' is a charade indicator (letters next to each other).
'the melody' becomes 'tune' (synonyms).
'right' becomes 'r' (common abbreviation).
'tune' put next to 'r' is 'TUNER'.
Can you help me to learn more?
(Other definitions for tuner that I've seen before include "Adjuster of pianos" , "Motor specialist" , "Radio receiver" , "Piano adjuster" , "piano man?" .)