Go faster than old-fashioned quiet expert (7)
I believe the answer is:
outpace
'go faster than' is the definition.
(I've seen this in another clue)
'old-fashioned quiet expert' is the wordplay.
'old-fashioned' becomes 'out' (as opposed to 'in').
'quiet' becomes 'p' (music symbol for 'piano', ie soft or quiet).
'expert' becomes 'ace' (ace can informally mean very good).
'out'+'p'+'ace'='OUTPACE'
(Other definitions for outpace that I've seen before include "Excel in speed" , "Go faster than" , "Walk faster than" , "Overcome by speeding" .)