Recapped July 1st 2026 - Another White Whale listing from Lutz Mumtimedia, we have the extremely rare PS1-B with the incredibly rare variable SPEED CONTROL KNOB In working order! It’s kind of odd, the last two switches don’t seem to do much, and the speed knob only works until you hit about 70% and doesn’t seem to do much after that. However, the unit was just with modern components so maybe that had something to do with it? It used to be quite noisy and now it sounds awesome. Either way, it’s a killer phaser in great working order! Ready to go.

I’ve owned and sold dozens of these, but I’ve never even seen one with a variable speed control knob before. An extremely low number of these were ever produced and even fewer survive.

• The PS-1 was Maestro’s original phase shifter (ca. 1971) and is often cited as one of their more widely known vintage effects.  
• The PS-1A variant (which has fixed-speed settings) is more commonly encountered in vintage pedal circles.
• The PS-1B is a very uncommon alternate version to the standard PS-1 line, with the additional feature of a handy variable speed control which were not in the original!
• In enthusiast discussions, people note that “far more PS-1A versions were produced than either the PS-1 and even far fewer were the PS-1B versions.”  
• Because far fewer have survived (or been traded) in collector circles, sightings or listings of PS-1B are extremely rare to find and highly coveted.
• This particular PS-1B also has the optional and even more rare upgraded Mullard tropical fish polyester film capacitors (as shown on the PCB), giving it an even rocker and thicker 3D sound.

the last PS-1 that sold went for $1600! The variable speed co tool makes this even more desirable in that you can dial in the phaser speed to match the tempo of the song you’re playing live or working on in the studio, to add to the rhythm and vibe of the music, in real time.

Any questions please ask. Thanks for looking. Open to trades. Have a good one