Preamp-Power amp- speakers for guitar?

[immunoglobulin]

Hey guys,

I want to set up a rackmount amp for recording and live. I thinking of buying a guitar preamp that digitech and roland offers or focusrite's trackmaster pro.

I'm thinking of hooking them up to a power amp that is lying around in my living room and then straight into the JBL's speakers.

Can this setup work as an amp? I'm not really familiar at how an amp works but this what i've gathered from doing some research on my own.