"Tube Sag" at Any Volume - Compressor in the Effects Loop

In this video I show how to simulate "tube sag" - the natural compression effect caused by cranking a tube amp so loud it overloads the power supply - by using a compressor in the effects loop of any amp.
Equipment Chain:
Guitar (Duncan JB bridge pickup)
Muku Looper
Mesa Mark V (crunch channel)
Behringer CL9 Compressor/Limiter
Mesa Mark V (power amp)
Mesa Recto Standard Slant Cab (Celestion Vintage 30s)
Shure SM57
Zoom H4n Pro