Without knowing the make/model of your amp it's hard to say,but a look in the instruction manual should tell you the fuse rating.
Pioneer PDP-LX5090/BDP-LX71,Humax HDR/9300T,AB-IPBox,Mac Mini,Beresford Caiman,Roksan Kandy MKIII,Arcam AV9/P7,PMC FB1i/TB2M-Ci/DB1i,BK Monolith DF,Chord cables,Tacima CS929