As a comment on the above.

You have to bear this in mind: I live in a country that uses 240 volts AC, but AFAIK the basis of 110 Volt AC supplies as per the US is similar, baring the voltage [and AC frequency] of course.

It looks like you have wired this up correctly, but I cannot confirm if the switch is breaking/switching the correct wire.

If you got it wrong, then the brick will still power up/down like it supposed to when you use the switch.
The DC will still have the right polarity as the AC is still AC whether hot/+ and ground (called Neutral over here) are swapped.

The only 'bad' side effect would be if the power brick has a internal thermal cut out to protect against fires due to overheating (most powerr bricks do I believe to get certified), and then an electrical short develops in the power brick due to over heating, then maybe the thermal cut out might not stop the power brick from conducting voltage to places where it shouldn't go.

However thats a big if.

To be 100% certain, get a AC rated double pole switch - i.e. a switch that can switch both hot/+ and Ground leads off or on at once, that way you're covered.
But that means 4 wires to solder (i.e. twice as much soldering of wires to switches than you've done already).
You have to make sure that you connect these wires up correctly otherwise you will cause a short circuit or something worse when you plug it in!
[or the Empeg won't go].

Oh and you ARE going to put lots of insulation tape around all those bare live wires right?

Especially as the Empeg sled is all Metal and we all know how much Metal loves to conduct electricity and any shorts against the empeg sled could send your empeg to MP3 heaven [and any owner touching it at the time along with it too possibly].

I know that 110 Volts is not supposed to be fatal, but try it with wet feet on a damp floor and see if it feels non-fatal to you at the time.
And in any case, the old heater in the bath/spa-pool sure looks fatal in movies at least.

BTW: You could consider doing what I did on my docking station - I installed a 240 volts rated micro-switch into the rear of the sled, which acts like your switch does - except the docking/sliding in to the sled of the Empeg switches the AC to the power brick on automatically, to power down, undock the empeg sled slightly [or remove the empeg altogether].

This feature saves inefficiency in running the power brick when no empeg is attached [doing my bit to reduce CO2 emissions by a tiny fraction].
Of course I insulated the wires going to and from the micro-switch really, really well - that metal chassis is not that far away from the 240 volts!

BTW: I don't have a digital camera [yep, must be just about the only person left on the planet without one], so I can't post any pictures or close ups.