Just recently I was trying to figure out the fx loop levels to match my Boss GT10. The way I had set it up was to plug the GT10 directly into the return of the loop and just use the GT10's amp models, bypassing the 2466's preamp as I'd figured the strength of the 2466 was in the poweramp.
Despite many attempts at tweaking the GT10, I could not get a sound that I was entirely happy with.
The same thing happen today. Frustrated, I tossed the GT10 aside, and just plugged my strat straight into the front end, set it to high dynamics, mid boost in, cranked the detail and body, dimed the eqs, lowered my guitar volume to 2-3, and there it was! The TONE!
What was I thinking, trying to use the Vintage Modern without its preamp?!
The GT10 is now relegated to just providing mod and delay effects in the 2466's loop...