The Four to One mixer is a simple and compact 4 channel mixer with independent level controls and selectable phase for each channel. This was primarily designed to be used with our One to Four Splitter to create 4 parallel signal paths, but it can be used just about anywhere you need to mix four different sources into a single output. This high headroom device features a high 1 Mohm input impedance and a low 100 ohm output impedance ensuring all signals maintain their sonic integrity, even on long cable runs. The high headroom input impedance of this device allows it to accept a variety of instruments without distortion or clipping: guitars, basses, synthesizers, drum machines, and more! The Phase selector switches for each channel will make sure to correct any issues you might have from mixing multiple different signals with opposing polarities. When used in conjunction with the Four to One Splitter and our Flexi Loops™, you can create wild parallel signal paths at the flip of a switch! "¢ Phase -/+: Use this to select the output phase of the channel. Sometimes other pedals and various instruments will invert the phase of the signal, which causes major problems when mixing with other non-inverted signals. If you have a signal that is inverted, flip the phase switch to -" and the polarity will be corrected. In most cases, this switch should stay in the "+" position. "¢ Level: Adjusts the output volume of the channel."