I have the Ceriatone 1968 Super Lead 100W head. I love this thing. My question is this. I have a choice of cranking both channels and then using the PPIMV or, cranking the PPIMV and both channels and then using an attenuator. What is the difference...in other words, what is happening to the circuit in both scenarios. A friend came over the other day, and we A/B'd the two choices as best we could, on the fly in real time, so that I could get a feel and sense of what the amp sounded like and felt like, but with other distractions and such, I hate to say that I was a little disappointed at the lack of definitive results.