Here is what echo park has to say on their Super Freq:
"Our Latest pedal creation. Gives you a Dual Stacked Overdrive with frequency selector. This Vintage style tone control is set up to engage on channel two. The 1st position on the 6 way tone switch is bypass. The frequencies roll off from there, 2 to 6. The middle toggle switch controls the passive coil split.
Up engages 100% coil, and down engages 50% coil, giving you a whole set of 5 more subtle tones. It may be necessary to up the amp volume or one of the overdrives to compensate signal cut. This unit in skilled hands can be used to dial out unwanted frequencies, or feedback coming from other pedals in the signal chain.
The Super Freq prefers a dedicated power source from your power brick,
instead of being “daisy chained”.
The passive tone unit does not work well with wireless units.
There are two separately voiced overdrives 1 and 2. 1 is slightly warmer.
2 has slightly more gain. Channel 1 engaged, will not engage the tone selector, unless Channel 2 is engaged.
Power jack is 2.1mm 9v center -NEG. No internal Battery.
Made in America"