Master Mute
Hit the mute pushbutton on The Underfacer to mute your signal before it reaches your amps. No matter what craziness is happening on your board, the master mute has the final say on what does or doesn’t get sent to your amp.

You can also control the master mute with RMT remotely on top of your pedal board.

Summing
The Underfacer has two types of summing: Stereo Sum and Split Sum. To access these two modes, use the internal DIP switch to select which mode is best for you.

Stereo Sum – This is the default mode The Underfacer ships with. In this mode use stereo effects as normal. When summed, the left and right inputs are merged and the exact same signal is sent to the left and right outputs.
Split sum – Still use stereo effects as normal. When summed, the right input is ignored and the left input is split to both left and right outputs.

RMT
RMT can be used with The Underfacer to access the summing mode and master mute.

Summing – Hold the foot switch on RMT for more than 2 seconds to switch the sum state to stereo or dual mono. The LED on RMT will blink once the change has been made.
Master Mute – To mute or un-mute your signal on The Underfacer using RMT, tap the foot switch. Yup. Easy.

Ground Lift & Phase Correction (The TX Underfacer only)

The TX Underfacer comes with ground lift and phase correction for players that want to run more than one amp.

Ground Lift – There are times when two amps are being used that an audible hum/buzz can be heard coming out of your amps. When plugged into one amp only, the hum/buzz is not present. This is commonly referred to as a ground loop. This happens when there is more than one path to earth. To safely fix this common problem, a transformer is needed to isolate your second amp and create one path to ground. Push the red ground lift button to isolate your right amp from your left.
Phase Correction – Another common issue when running two amps is phase cancellation. Some amps are in phase in relation to each other and other amps are not. When amps are out of phase with each other they are cancelling each other out. This is most noticeable in the lower frequencies. Normally this would mean you can’t use those amps together. With the black phase correction button you can now put two amps that were out of phase, back in phase and working together. To access this, turn on the transformer (red button) and flip the phase (black button).

Input
The Underfacer comes with a buffered input. This means before your guitar sees the first pedal on your board you are sending a high impedance signal to your pedals, preserving your tone. The Underfacer also comes with an always on tuner out.