Who may change a few notes for a grand (5)
I believe the answer is:
'grand' is the definition.
The definition and answer can be both man-made objects as well as being singular nouns.
Maybe you can see an association between them that I can't see?
I can't explain the rest of the clue.
Can you help me to learn more?
(Other definitions for tuner that I've seen before include "piano man?" , "Radio receiver" , "Motor specialist" , "Piano adjuster" , "Radio adjuster" .)