Fuse upgrades? -- 6.3 amp 250v 5X20mm fast blow fuses


I occasional blow a one of these 4 fuses in my McCormack DNA .05 and use cheap fuse replacements costing maybe $.50 a piece.  Can anyone recommend upgrades fuses that might enhance the performance of the amp, but not costing in the SR price range.  Say $1-$5 a piece?   Thanks for any insights.    
whitestix
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Cooper-bussmann (USA), LittleFuse(USA), Schurter(Germany) ....and the the favorite of the Japanese audio business for over 50 years, SOC of Japan.

look for long lag fuses from any of those companies, and you'll be part way to the higher end audio grade fuses for a few bucks a pop.

Make sure you replace with the same type (fast low, normal blow, and lag types) as the manufacturer recommends.