Here’s the most useless pedal I owned . Not kidding , it’s useless !
Ok it’s a bit mean but honestly I don’t get what’s the purpose of this pedal. It isn’t a phaser , it could be a vibrato but also a tremolo, maybe both. I kept this for 2 months . I didn’t know what to do with it . I could modify it but i’ve other projects to finish . And also some Adurnio projects to learn. I traded it for a Boss volume pedal that I needed .
electronicaly it’s phaser with 3 phase stages followed by a standard OTA varaible gain. The trick is that there’s no dry signal mixed back with the “phased” signal , so no phaser but vibrato ! But not as deep as a traditional 4 stages phaser (the 4th Ota is used as variable gain (tremolo) ) and like any other vibrato the effect is more pronounced with high speed . The issue is that the frequency of the phase seems to be set lower than usual therefore the vibrato is more located on bass frequencies. Intensity of the tremolo and the phaser can be set independently but the speed remains the same for both. There’s a feedback (or “resonnance”) pot for the vibrato.
I think that if the dry signal (after the input buffer) is mixed with the phased signal at the input of the last Ota and C8/C9/C10 are changed for lower values the phase will go up in the frequency range the pedal will be a “real” phaser with the addition of a tremolo. But still with only 3 stages (think MXR phase 45 for exemple). It might be really nice. I thought about doing these mods or at least try them .
here’s the schematic : https://smokingtip.files.wordpress.com/2013/06/fx22.pdf