Keyboard instrument only audible when it has the lead? (8,5)

I believe the answer is:

electric piano

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'only audible when it has the lead?' is the definition.
I know nothing about this answer so I can't tell whether it can be defined by this definition.

'keyboard instrument' is the wordplay.
'keyboard' becomes 'electric' (I am not sure about this - if you are sure you should believe this answer much more).
'instrument' becomes 'piano' (musical instrument).
'electric'+'piano'='ELECTRIC PIANO'

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I've seen this clue in The Times.

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