on your preamp, i would think that it has outputs for left and right. those would connect to the inputs on you 400 amp. should be easy.
Hooking up my phase linear model 2000 preamp, to my model 400 main amp.
I had these two units for years,hooked them up back in 2001,found they needed some work, had them repaired they have sat in the shipping box ever since. I did hook then up years ago but don't remember how I did it. Now I have them again, and want to get them going . And don't want to burn something up hooking them up wrong. Can someone give me some direction how to do this. Thanks DRW.