Variac vs Voltage Supply Sag Effect in a Fractal Plexi

In this clip you will hear the difference between Variac and voltage supply sag in the AxeFxIIXL+ on a Marshall Plexi:

Four parts:

1. No Variac or Sag
2. Variac down to 75%
3. Variac down to 75% and Sag control about 50%
4. Variac down to 75% and the Sag control maxed out (Neil Young approved Mush City)

Guitar: PRS Hiland rear pickup (59/09 in this case) split for single coil sound