The MXR Phase 90, probably the most popular Phaser Pedal (especially since Eddie Van Halen used it). The Phase 90 is a JFET base Phaser circuit.
It uses 4 JFETs which needs to be matched to get proper phasing. For my build ive used a Madbean NomNom PCB and a matched JFET Quartett from Musikding (2n5952)
You mach the JFETS by yourself too. Instructions for this are in the Madbean NomNom build doc.
All parts except the JFETs are very easy to obtain.
For my build ive used following mods, which are the original does not have:
- Rate LED (which is also used as bypass LED)
- Feedback switch (intesifies phasing, when on)