Syntaur
"Syntaur's Sam Mims install the prototype of Analogue Renaissance's REV -1 into a Prophet 5. This amazing board replaces the CEM filter chips in a Rev 3 Prophet, and dials it back to the sound of the highly coveted Rev 2! Additionally, it adds two switches which allow the selection of either 4-pole or 2-pole filtering, and which add Q-Compensation, to make up for bass frequencies that are normally lost with high-resonance sounds. The sonic result is beastly! The REV -1 kit can be purchased here: https://syntaur.com/Items.php?Item=REV1"
via this auction
"Sequential Circuits Prophet 5 Rev 3.2, with MIDI and Analog Renaissance REV -1 Kit installed. This synth has been fully calibrated, and all key bushings have been replaced, to ensure years of playability. Aside from a small crack in the wooden right end panel (see photos), this unit is in excellent physical condition.
The REV -1 kit from Analogue Renaissance turns a Prophet 5 Rev 3 synthesizer (CEM filter chips) back to the sound of the highly-coveted Rev 2 (SSM filter chips). It also adds a 2-pole/4-pole selector switch for the filter, and a 3-position 'Q Compensation' switch to add back in low frequencies that are typically lost with high resonance sounds."
