Virtuoso left band — no piano turning up (7)
I believe the answer is:
maestro
'virtuoso' is the definition.
(both can mean a great musician)
'left band no piano turning up' is the wordplay.
'left' says the letters should be written in reverse.
'band' becomes 'seam' (band of material).
'no piano' becomes 'ort' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'turning up' says the letters should be written backwards.
'seam' back-to-front is 'maes'.
'ort' in reverse letter order is 'tro'.
'maes'+'tro'='MAESTRO'
(Other definitions for maestro that I've seen before include "Gifted performer" , "musical genius" , "great musician" , "Top player" , "special performer" .)