Avoid 7 Cable Method (2 amp FX loops)! 

I am running a setup from home that doesn't need to travel and I have been considering doing something exactly as you describe in this video. Currently, I am running from guitar into one impedance sensitive fuzz pedal, and then out to a passive saturnworks splitter/combiner, to provide one DI for possible later reamping. That comes back to a PJ predrive where I could then switch to the line level source for reamping. After this, it is pretty standard, going into a ML10X which is where it splits and provides another long chain of stereo pedals and eventually to the inputs of amps on either side of the room. As much as I love trying dirt boxes I cannot seem to get anything sounding as awesome as the gain channels on the main amp in this config which is a Mesa Mark Five:35, so I am thinking to do what you show with splitting the effects send at the ML10X and returning to the mesa and the other side to the effects return of THD BiValve being used as my second amp for stereo. I currently have no solution for phase or ground loop, and in the current setup I already notice what sounds like hum, but haven't much of a good way to know about the phase other than trying to A/B. So if I'm understanding correctly, there is no potential for ground loops in the effects pedals themselves, because their circuits are actually DC, even though the DC supplies are from an AC source? The other thing in my current setup is I have the cab clone of the Mark Five going to my interface via XLR, and I have a Digitech CabDryVR before the BiValve to provide the amp and cab simulation for the other side of my stereo configuration to the interface. I use that one because it can pass through for the amp. I'm assuming there could be potential for ground loop at these locations, or even all the way back to my initial splitter. Even if I switch to having the Mark Five preamp pushing everything, where could I improve on ground and phase problems?

I tried this exact setup today and it sounded great. I have a radial big shot aby that goes to a tc electronic ditto x2 which allows me to loop a rhythm and then switch to one or both amps for leads. The effects loops of each amp goes the left and right of my wet effects.

I agree with this video 100% I do run 7CM + I have a loopswitcher that doesn't have an iso transformer. It was a B to figure out. In the end I have to use 2 ISO's. 1 is my ABY box that goes into my loopswitcher input and 2. That ISO is directly wasted cause the switchers sums it back together. And the second one is right after the switcher output 2. I have an 4cable noise gate in both the amps effects loops and both go through a boss RV500 voor time based stuff. If you would draw it out and see how many loops and problem points there are in this setup you would pull your hair out.

An easier solution for stereo... just use Axe FX or Quad Cortex or any amp modeler (L & R) into 2 cabs.

for a while there, i felt partially responsible for this awesome tutorial/video until you said you get asked this every week, I guess maybe I was the straw that broke the camels back, which kind of makes me feel better. A pair of questions have arisen through watching this though, 1. If running the dreaded seven cable method with two identical amps, would that only solve the leveling of the loops? 2. If running the high five cable method, the return of amp two, or i guess with the returns in general, returns aren't what need to be leveled but the sends? Thanks again for the information last week and responding to my email. Not going to lie, I'm kind of bummed, because I want to blend the sounds of my two amps together while utilizing some stereo effects both in front, or at least mono effects being sent to the front end of each amp, as well as stereo effects in the loop, but apparently I want too much.

What advice do you have for building a pedal rack to run stereo pedals before and after a DAW based software amp-sim insert within an outboard pedal rack unit? It would be going into a stereo-in instrument level audio interface (with separate stereo line level I/O for the post-amp effects). I am looking at the Radial EXTC Stereo and Morningstar ML10X MIDI switcher - and then using the Radial as one of the assignable loops to place between dry and wet loops. Do you foresee any grounding or impedance issues?

How would this translate to HX effects? When using it with two Bluguitar AMP1’s?

No phase issues