Guys, thanks for all the excellent responses!
I now have some receptacles and plugs. I bought 2 different types because I was not sure if I needed a 3 or 4 wire (Hubbell HBL2320 and HBL2410) while at the store.
I should have mentioned that the amp (originally from Europe) 220V but uses 1 hot, 1 neutral, 1 ground, like 120V in USA/Canada. I noticed that the new HBL 2320 receptacle uses 2 hots and 1 ground...Can I use this?
The HBL 2410 has 4 wires...I believe this is wrong for the application.
Jea48 - I actaully have 2 unused dedicated 120V lines, I wanted to connect both hots to make 240V. I am sure you are right about my voltage, it will be 250V, since I get about 125 on a single line. I was hoping to connect the 2 hots, a neutral and ground, then emulate what is happening in Europe.
Ngjockey - I don't know why this would be out of phase when the breakers are on the same buss bar? I am not trying to tell you that you are wrong...just trying to learn. Also you mention to cheat and put 2 hots on a 3 prong outlet...but I think that is how it looks on my oven for example.
Thanks again guys!
Mike