Subwoofer amplifier

Andrew, appreciate your reply & assistance. My apologies, what do you mean by "add a light bulb?" Do you mean and ordinary light bulb attached to the main line? By the way, there is no switch between the cord and the amp- just a plug that goes straight to the amp. Can improper grounding do this? I'll take a picture and this would probably help you.
 
Yes. There are rules to how much current a slow blow and a fast blow fuse should take before braking the circuit. In addition there are rules about the slow blow fuse in respect of how much current it should withstand (times its rating) without braking.

These rules are correlated to time: should blow within x milliseconds or should not blow before x milliseconds if a defined multiple "y times its rating" of course depending of if it is a slow blow or fast blow one.

So for a slow blow type the stipulation could be like this:"should not blow within x time if the current is 2 times its rating but should blow within x time if the current is 5 times its rated value.

Slow blow types are used for instance on the primary side of a mains transformer where the start up current is high before the current through it builds up a magnetic field that "opposes" the changing direction of the AC current.

Fast blow or even super fast blow types are more common when it comes to protect sensitive devices like semiconductors.

Markings in accordance with IEC: FF = super fast . F = Fast . M = Medium fast. T = slow.
TT = very slow.