Tamper with sound of gong (6)
I believe the answer is:
meddle
'tamper' is the definition.
(I know that meddle is a is a more specific form of the action of tamper)
'sound of gong' is the wordplay.
'sound of' shows a homophone (sound like).
'gong' becomes 'medal' (gong can mean a prize or medal).
'medal' sounds like 'MEDDLE'.
'with' acts as a link.
(Other definitions for meddle that I've seen before include "Interfere in other's business" , "Intervene" , "Interfere in someone else's business" , "Pink Floyd album" , "Interfere in people's affairs" .)