The high end half of the bassist from ANTA was giving him shocks. He played through it.
PCB mount pre valves and noodle lead dress, meh. Its had a recap, but on that tag strip tot he left, the infamous death cap. Measures resistive on the meter, so leaking a fair bit of mains though. Live chassis, live bass, live bassist. Not really ideal.
The chassis is earthed so leakage would generally take this path of least resistance. However:
Live and neutral leads should be cut shorter than the earth, kind of why plugs are laid out like that, so earth is the last to pull out. This one they are are all same length and bundled in, so a tug on the wire pulled the sleeve from the strain relief and disconnected the earth. Edit: just been pointed out that US wiring scheme is black is live, so live and neutral are reversed. Still works like that, but the fuse is in the wrong place.