Afaik, preamps have a very low volume Output, so you need a poweramp of any kind. The Tech was a poweramp (as it says power engine) http://www.tech21nyc.com/products/powerengine/powerengine60.html. Many People, i read, use a rocktron poweramp. I go through a tube Combo with fx-return. I heard some very good sounds with a mesa rack poweramp as well.
I think pretty much everything works, as long as it sounds good to you.