what is signal gnd on a sony amplifier?

Answer 1

My Sony amp only has two wires to the plug, the signal ground is for, a) connecting to the ground (literally) but if you are in the U.K. if you run a wire from the Sig grd to the earth pin in the plug that's O.K. b) if you have a turn table (record player) it needs a connection to ground to cut down Hum, c) if like me you have a bit of kit that gives you shocks run a wire (I have sellotaped a wire to the metal case) to the Sig grd and no more shocks.

Answer 2

The cartridge in a record turntable needs a positive connection to earth (ground).

Some amplifiers offer this connection on the back panel.