Band leader equally quickly producing instrument (7)
I believe the answer is:
bassoon
'instrument' is the definition.
(bassoon is a kind of instrument)
'band leader equally quickly' is the wordplay.
'leader' indicates taking the first letters.
'equally' becomes 'as' ('as' can be a synonym of 'equally').
'quickly' becomes 'soon' (I've seen this in other clues).
The initial letter of 'band' is 'b'.
'b'+'as'+'soon'='BASSOON'
'producing' is the link.
(Other definitions for bassoon that I've seen before include "Instrument heard by Wedding-Guest" , "Double-reed instrument" , "wind player" , "So-so ban on the instruments" , "No, a boss would be a musical instrument" .)