Producer of notes and letters from abroad in charge of fight (5,3)
I believe the answer is:
music box
'producer of notes' is the definition.
Although both the answer and definition are singular nouns, I can't understand how one could define the other.
'letters from abroad in charge of fight' is the wordplay.
'letters from abroad in charge of' becomes 'music' (I can't justify this - if you can you should give a lot more credence to this answer).
'fight' becomes 'box' (boxing is a kind of fighting).
'music'+'box'='MUSIC-BOX'
'and' is the link.
Can you help me to learn more?
(Another definition for music box that I've seen is " What plays when opened".)