When an amp is blowing fuses, you need a way of limiting the current it draws so that it gives you enough time to check and see what's causing the problem. This can be done by putting an incandescent light bulb in series with the AC cord to the amp. The wattage of the bulb will limit the maximum current based on:
wattage=amps * voltage
so a 100 W bulb will limit the current to roughly 1 amp, a 40 watt bulb will be about 0.4 amps, etc.
Using a standard wall box for a house and an AC receptacle you can build a device to make it easy to put a lamp in series. The AC receptacle can be split by breaking a tab so the two jacks are separate. Then one jack can be wired in series with the black wire so that a lamp needs to be plugged in to
complete the circuit. The other jack is where the amp plugs in. I put one of these on my variac. With a shorting plug in the series jack it works normally. Pull the shorting plug and plug in a lamp and you have current limiting with a variable voltage.
Do a Google search on "light bulb current limiting' and you'll see lots of clever ideas for implementing this.
The light is also a indicator of what's happening in the circuit. If it comes on full bright, there's probably a short to ground. In a normal circuit it will glow softly. In a tube amp you can see the initial current surge as the filter caps charge (that's why Slo-Blo fuses are needed), then then glow will soften.