MXR™ Phase 45™

These are instructions for some of the many modifications that you can make to your MXR™ Phase 45™ project. These modifications are based on modifications by J.C. Maillet that have been posted on his site for years. We did some modifications to his modifications. We found that his modification #5 “Mix” control did not work as we expected and is difficult to tune it in to vibrato or intensity. So we provide some alternatives here. Modification 1: Add an Intensity Control. To do this you will replace Resistor R9 (10k value) with a 10k linear taper pot. Wire it has shown in the Modifications Wiring Diagram. This seems like a strange way to control the intensity of the phase effect, but we found that lowering the resistance here fades out the phase smoothly and this is the most straight forward simple method we found to do that. Another option is to add a 100k pot after R9 and as you raise the resistance, the phase effect will also fade. We found the 100k pot solution to not have as smooth of control as the 10k pot we implemented. Modification 2: UniVibe Me! This is the most awesome of all the modifications. This really works well. Just replace Caps C2 and C3 with 10 to 1 value ratio, a 0.1uF and 0.01uF cap and you get a more pulsing effect very similar to a UniVibe. The modification can be a replacement of the caps to have a permanent UniVibe-type effect, or as we have shown in the wiring diagram and schematic you can make it switchable from stock Phase Shifter to “UniVibe Mode”. Modification 3: Vibrato Mode Control. The sound of “Phase Shifter” is created by mixing a warbled sound with the dry sound. If we remove the dry sound, you are left with a warbly pitch-vibrato sound. We have found that phase shifters usually don't give a very strong vibrato when you cut the dry mix and this is the case with the Phase 45™. We have included the mod here because some folks might like the subtle effect and want to know how to do it. To Implement, just cut the dry signal line and put in a simple on/off switch to be able to switch the dry signal in/out as we did with Sw3 in the schematic and diagram. We hope you enjoy tinkering with this beautiful effect stompbox!