thats what my amp tech did for me, he said the initial start up blew the fuse. The amp is a bit problematic though.The filament circuit has a fuse that's rated too low in this amp, 6.3 amps IIRC. That's probably the one that keeps blowing. In general it's a bad idea to go higher with a fuse rating but in this case you can. Try a 10 amp slow-blow, you shouldn't have any trouble with it anymore. P.S. if you're not sure which fuse to replace, take it to a tech.