The AMPEG R-12R is a 50w amp with two channels. has two channels, clean and drive. You can switch between the two channels either with the channel switch* on the amp itself, or by plugging in the foot switch and hitting the left button.
The treble, mid, and bass knobs are normal EQ controllers.
The clean channel uses only the “volume” knob on the amp – not the gain or master.
The drive channel uses the gain and the master knobs, so you can hone in the distortion.
The reverb knob measures the amount of the amp’s built-in long-spring reverb.
The foot switch allows you to switch between channels, and turn reverb on and off. During live recording, this can be used to switch from rhythm guitar, which is typically cleaner, to lead guitar. *When the foot switch is plugged in, it bypasses the channel switch on the amp.