The Electro-Harmonix Tri Parallel Mixer is parallel effects-loop pedal and also a mixer and a switcher, depending on how you're operating the pedal with your guitar or bass. You can use it creatively to achieve tones unavailable through connecting your pedals in series. You can also use the pedal to solve problems on stage such as switching among multiple instruments.
You'll note three different effects loops, each one selectable via footswitch. Each loop has its own control over Send Volume, Return Volume, EQ, and Phase. The Phase control is particularly useful if a parallel effect returns to the Tri Parallel Mixer out of phase, and needs a polarity flip to return fullness to the signal. Use the EQ control to give you more treble or bass if needed.
You can turn on these effect loops in AND mode, which allows you to turn on various combinations of all three loops. Or in XOR mode, you can select one at a time. In XOR mode, you'll automatically turn off all the other loops every time you select your independent channel. Both modes give you creative options to explore.
You can use this pedal to switch among loops, sending one instrument's signal to multiple amplifiers at once, switching among different amplifiers, or mixing/switching multiple instruments that feed one amp. Whether you want to send your electric guitar to three amplifiers, or send three different guitars to one amp, you'll find this pedal triply useful.
You'll find global controls such as Master Volume for overall level and Dry Volume to raise and lower the level of your unprocessed tone. The Tri Parallel Mixer comes with its own power supply.
Send Knob: This knob sets the level output to a channel's Send jack.
EQ Knob: This knob affects the tonal characteristics of the signal input to the Return jack. When the knob is at center, there is no effect. Turn the knob up for more treble and turn the knob down for more bass.
Phase Switch: This switch, when set to 180°, inverts the phase of the signal sent out of the SEND jack. This can be useful when something in your effects loop is causing phase issues when mixed in with either your dry signal or other effect loops.
AND Mode: Use any combination of all three FX loops at once.
XOR Mode: Only one FX loop can be used at a time. Selecting one loop automatically deselects the others.
Return Muting Mode: This mode allows you to always feed signal to a secondary output, while retaining the ability to mute/unmute the primary output of the pedal.
Instrument Switcher: Plug up to three instruments in each dedicated Return jack and then set the Tri Parallel Mixer to XOR switching mode. When you click a channel, you can now select among your instruments, using each Return knob to govern the level of an applicable instrument.
Multiple Output Routing: Use the Tri Parallel Mixer to send a guitar to two separate amplifiers. You could either switch between the two amplifiers, or send your guitar signal to both at the same time. Use the Send knob for a given channel to set the level of the signal sent into the amplifier.