Wealth coming to composer, man of musical variations (8)
I believe the answer is:
goldberg
'man of musical variations' is the definition.
(reference to Bach's Goldberg Variations)
'wealth coming to composer' is the wordplay.
'wealth' becomes 'gold' (gold is a kind of wealth).
'coming to' means one lot of letters go next to another.
'composer' becomes 'berg' (20th Century Austrian composer).
'gold'+'berg'='GOLDBERG'
(Other definitions for goldberg that I've seen before include "harpsichord variations" , "Bach wrote the - Variations" .)