Not sure what/why this need for a processor loop. Just use an ic from "fronts"-out on the processor,to another input on said pre. When doing ht,change inputs on the pre,to that input,do the "test" thing,see where the volume needs to be.It stays at that level for HT.Just so you don't rule out a pre baised on "no loop".
If you had to make this decision....
I'm looking for some advice on preamps for my system. Aside from sounding great, a remote and HT loop/direct would be useful. I've heard the BAT50SE, CJ16LS, Melos 333 and Levinson 38S. None of these jumped out as clearly better. My system is Levinson 31 -> Audio Logic DAC -> Meridian 568 -> VTL MB750 -> Magnepan 3.6R. Any suggestions on what else to try?