Gibson GA-20 Owner's Manual page 15

be sure to use a quality, unshielded speaker cable and only connect to speaker cabinets which
are rated equal to the output jack you are using. For example: a 4X12 speaker cabinet, rated
at 16 ohms, should ONLY be connected via the "16 ohm" output jack on the rear of your
amplifier.
Main Fuse — GA-20
100V~/120V~ (Japan/U.S.A) use 5 x 20mm T1.6AL250V (Slo Blo) fuses.
230V~ (Europe/U.K.) use 5 x 20mm T800mAL250V (Slo Blo) fuses.
Main Fuse — GA-40 and GA-42
100V~/120V~ (Japan/U.S.A) use 5 x 20mm T1.6AL250V (Slo Blo) fuses.
230V~ (Europe/U.K.) use 5 x 20mm T1.25AL250V (Slo Blo) fuses.
Power Cord Connection
Your amplifier shipped with a power cord appropriate for the country in which you purchased
it.