A little music, one allows, has charms (7)
I believe the answer is:
amulets
'charms' is the definition.
(an amulet is a charm or talisman)
'a little music one allows' is the wordplay.
'a little music' becomes 'amu' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'one allows' becomes 'lets' (I've seen this in another clue).
'amu'+'lets'='AMULETS'
'has' acts as a link.
Can you help me to learn more?
(Other definitions for amulets that I've seen before include "Lucky charms" , "Ornaments worn as charms against evil" .)