i recently did a gig and my gear got thrown around a bit. whenever i don't touch a metal part on my bass i get this terrible hum. now the first thing i tought of was that it was a ground problem so i did some measurements with my multimeter, my cable's ok, as is my bass (there's a good connection between the ground and my strings) and the connection between the ground at the input plug and the ground at the ac wall plug is also ok.

now i don't have a clue as to what could be the problem :-(
That's odd.

Can you get ground problems in your amp?
Maybe its a ground loop in your power sockets?

Did you pull the input plug out and check if the ground came off or not?
PRS SE Custom 24
Jackson DKA7
Gibson Explorer
MESA/Boogie Express 5:25

Dunlop Cry Baby Classic
VOX Joe Satriani Ice 9 OD Pedal
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Ernie Ball Strings
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Anyone else read it as Cum Humming?

Gibson 2005 Les Paul Standard
Fender Road Worn Strat w/ Noiseless pickups
Marshall JCM 2000 401C
Marshall Vintage Modern 2266
Marshall 1960A cab (Dave Hill from Slade's old cab)
Ibanez TS9DX
EHX Little Big Muff
Freshman Acoustic
i found the culprit, it's the fluorescent lighting (i moved my amp into another corner of the room)