Fixer of musical instrument is getting particular note right (9)
I believe the answer is:
organiser
'fixer' is the definition.
'musical instrument is getting particular note right' is the wordplay.
'musical instrument' becomes 'organ' (organ is a kind of musical instrument).
'getting' means one lot of letters go next to another.
'particular note' becomes 'e' (musical note).
'right' becomes 'r' (common abbreviation).
'organ'+'is'+'e'+'r'='ORGANISER'
'of' is the link.
(Other definitions for organiser that I've seen before include "bound to keep personal data" , "One managing" , "One who arranges things" , "Runner" , "One in charge" .)