As mentioned, the matter of having just one input would be addressed as while that would be fine if say you were using to improve on the sound of your tv with a small pair of speakers, it's not convenient for changing sources, having to plug and unplug every time.
So I got this.
It's really a A/v switch unit by HQ of Denmark for home theatre systems but having looked into the cost of buying the parts and a aluminum project case there would be no real gain plus I'd have buy a few beers for whoever was gonna drill and wire it up for me.
To connect it I bought a 0.5 metre Fisual cable as you really don't want long wires to take the output from this box to the input on the amplifier. I have 3.5mm mini jack for my Fiio X1 digital music players line output to plug into the switch and several Radio Shack (RIP) "Tandy Gold" thick oxygen free copper 1 metre cables.