Why did my amp just crash and burn ?

Sounds like you inadvertently shorted the spades across the speaker terminals.

That said, not too sure why you'd want to connect it the way you said you did. Weird, for sure.

Looking at pictures of the amp the fuse is in a tiny drawer just above the connector for the power cord.  The drawers are sometimes stiff to pull out but that is by design.  Also occasionally they contain a spare fuse.  

@ozzy62 Never do any of this work on your hifi when tired after work. I had long day and was ready for bed & decided to try and get it all done before hitting the sack. In effect do you think the cables are now useless ?

@drrsutliff Are you referring to the YBA YA201 ?, If you are then much thanks for doing that research. I now see what you talking about with the little slide out drawer above the power cord. 

Yes the fuses are generic. Your manual should have the Info on the fuse value. Be sure you find out if you need slow blow or fast blow.

@chaseton 

Nothing wrong with the cables. Replace the fuse and carry on. Hopefully that is as far as it went.