I watched a video on Reverand Willie / ZZ Top's guitarist using an EQ of some type that I'm trying to find out what type it was.
He would take a picture of the first guitar's EQ curve, and then later when using any other guitar, his tech would adjust the eq to get the same visual EQ curve with another guitar. This way, no matter what guitar he was using, he could get as to the same tone as possible to his favorite tone with his favorite guitar in theory, and could prove it basically using a visually on this EQ rack effect. What effect does anyone know of that might do this? I'd like to have this EQ for just the same reason, unless someone here know's of an easier way to do this?