Electro-Harmonix Tri Parallel Mixer Effects Loop Mixer or Switcher Pedal is a powerful effects creation and mixing hub with flexible controls for multiple configurations. The EHX Tri Parallel Mixer is a powerful effects creation and mixing hub with three separate FX loops and flexible controls allow for multiple configurations. The Tri Parallel Mixer is surprisingly compact considering the level of functionality it provides, while its intuitive controls and I or O make it easy to operate. Use it to switch between or mix up to three separate effects loops. Send a guitar or other instrument out to three separate amplifiers, or input three separate instruments to switch between or mix to a single output. Mix effects in parallel to create sounds and allow for options not possible when using effects in series (one after another).
RTN 1, 2, and 3 Jack
This jack is the input for a given channel.
SEND 1, 2, and 3 Jack 
This jack outputs the signal inputted to the Tri Parallel Mixer (via the Input jack) when its channel is active.
RETURN Knob
This knob sets the level of the signal received at the RTN jack before it is sent to the output of the Tri Parallel Mixer.
SEND Knob
This knob sets the level outputted to the Send jack.
EQ
This knob affects the tonal characteristic of the signal inputted to the RTN jack.
PHASE
This switch, when set to 180, inverts the phase of the signal sent out of the Send jack.
MASTER VOL
This knob sets the master output level of the mixer.
DRY VOL
This knob sets how much dry signal (the signal present at the Input jack) is sent to the output of the Tri Parallel Mixer.
OUTPUT
This jack on the left of the unit is the master output for the Tri Parallel Mixer.
INPUT
The signal present here will be outputted to an active channel’s SEND jack. In master bypass, the input signal connects directly to the Output jack.
CH 1, 2, and 3 Footswitch
This switch is used to activate or deactivate a given channel. Double-tap any of these switches to enter bypass mode. When in bypass mode, click any of these switched to enter active mode.