How is

What is two prong? RCAs or XLRs. Your preamp will have one or the other, UNLESS your "preamp" has amps on board also...

More information, what is the preamp, what are the monoblocks. Let me look up some stuff.... and get back.. .

First, make and model ay.. :-)

Regards...

Assuming that when you say you have two prongs in your preamp you mean left and right channel outputs, you just use one amp as your left channel and one as your right channel, and run the interconnects from the preamp accordingly.

Good question. I myself have often wondered how two mono amps is an upgrade.