I tried the following signal path based on a previous post as follows:

The input from the guitar goes to a preamp (Mesa FormulaPre)

The preamp output is via a "Send" from the Mesa

That Output goes to the Input of the Smartulator

The Output of the Smartulator goes to the "Return" of my OTS.

With this setup, neither the Volume or PowerAmp front controls knobs function.

Can someone explain what I am actually hearing from the speakers?

Thanks