Here is a very simple way to get a huge guitar sound with a minimum of components. The picture below shows a simple 8U rack with some standard issue guitar components – VHT 2/50/2 stereo power amp, Egnater IE4 preamp, and tc Electronics Nova System effect unit all running into an Old Dog 4×12 Xcab.
The dry signal goes: Guitar – IE4 – VHT Channel A – Top 2×12’s in Xcab.
Tip: Rewire a stereo 4×12 from Left/Right to Top/Bottom.
The effect signal travels as such: VHT Channel A – Line Out Box – tc Nova System – VHT Channel B – Bottom 2×12’s in Xcab.
Channels on the IE4 are changed via midi from the Nova system.

What is not to common in this setup is the transformer isolated lineout. This is similar to a Suhr Iso line out. It is needed because the polarity (in this case) needs to switch 180 degrees to keep the wet signal in phase with the dry signal. So, the line out does this for us.
The signal flow is shown below:

Another Tip or two:
-Run the tc Nova System input and output as high as possible (no boost). The higher the signal the better the fidelity.
-Adjust the input of the Nova with the level control on the line out.