Over the years I have read that the mud (tone) switch on Gretschs was not worth having; however I have recently been working out on a Setzer 6120, and have found the switch to be very useful. Granted it is not a tone pot, but it is faster than turning a knob; and I like what it does. I thought it also had a pretty valuable effect when using it in combination with an OD/ distortion box.