Probably due to the initial power-on/power-up surge. I had a Rotel power-amp that was fused in the same way for that reason.

You could always try a lower-rated fuse -- start with a 7a, then 5a and so forth. However, if the 10a fuse is needed then popping a lower-rated fuse may end-up causing undesirable results. I'd be inclined to leave things as-is.

Clem