Here s a copy of my post from another thread:
I just got a Line 6 M13 Stomp Box Modeler (SIICK!) and I run the 4 Cable method...
With the M13 you can assign 1,2,3 or all 4 FX banks to run in front of or in it's loop so...
I run the 1st 2 banks of FX in FRONT of the amp (OD's and Filters) and run the last 2 banks into the ElectraDyne's Loop (From the M13's loop). The results are FREAKING INCREDIBLE!
4 those who are unfarmiliar with this methos it goes like this:
Guitar into M13 Input.
M13 Effects Loop INPUT to ElectraDyne LOOP OUTPUT
M13 Loop output into Front of ElectraDyne
M13 Main OUTPUT to ElectraDyne Loop INPUT.
The Od's, distortions and Filters (Wah, Synths, etc) of the M13 sound GREAT in front of the amp and the Delays and reverbs really come to life running through the ED's Effects Loop.
TONAL BLISSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSS!!!!
I cannot say anough about the M13. I sold ALL of my pedals and pedalboard and don't miss them one bit now that I have the Line 6 M13!
Here's a guy using this method for his M13 and his Road King:
http://www.youtube.com/watch?v=kWd76YuCf1c