Upright piano in bash: tuning note ruined (8)

I haven't cracked this one yet — but the brilliant team at Times for the Times have:

P (piano) contained by [in] GO (bash) + A (tuning note) + L~OST (ruined). At the beginning of a concert, orchestras check the tuning of their instruments against the note A sounded on an oboe. I’ve used a tilde ~ to indicate the insertion point.