NU_NRG,
My idea is to shut down both rails. This would prevent the output from swinging to the other rail, and you hoping that other fuse blows before your speakers and/or cross overs.
The relay conatcts would be after the PS filter caps, so there would be zero volts into tamp very quickly. I agree with paulb, the PS is in the signal path. I don't know which is better to have in the signel path, relay contacts or a fuse. So I like the design that seems to be the most fail safe.
Chris,
You are talking about 2 protection devices. 1. DC sensor (the Velleman) and 2. Current limiter (the fuse) One does not replace the other.
Typically current protecting the input and voltage gain stages is not needed. You can concentrate on protecting the output stage.
You are using a very sensible (in my book) approach. Use a soft start to limit turn on current. Then you can use a fast blow fuse on the mains. (power transformer primary side) Use the lowest rated fuse that does not blow under normal listening situations.
IF and this is a big IF..... You are making mono blocks and the output stage is designed modestly, 4:1, 6:1 safety margin, the main fuse will go before the output stages.
Be carefull about that last paragraph. You must look at your design carefully and menatlly short out different devices in a game of "what if...."
Regards,
Aud_Mot