Sequential Circuits Prophet 600 – Gligli Upgrade

Sequential Circuits Prophet 600
Sequential Circuits Prophet 600

This Prophet 600 was brought in for a Gligli P600FW upgrade, which is a CPU/firmware upgrade using a Teensy ++ microcontroller board. It offers improved resolution for all parameters (128 values instead of like, 15 or 7!), a new LFO just for vibrato, arpeggiator MIDI sync and more, which you can read about here.┬áThe firmware is generously offered for free by the developer and in order to install it, we procure a Teensy 2++ board, do some modification to the Teensy, flash the firmware onto via USB, and install it in the Prophet 600 in place of the original Z80 CPU. We can do this mod for only about $100 including parts. Continue reading “Sequential Circuits Prophet 600 – Gligli Upgrade”

Sequential Circuits Pro One – CPU upgrade and MIDI retrofit

sequential circuits pro one synthesizer
Sequential Circuits Pro One

When we got this Pro One it was acting insane: keyboard playing only one note and/or pitch sliding upwards, loud bursts of noise, weird envelope/triggering behaviors. This synth is unusual for its vintage (early 1980s) in that much of the control voltage for the analog circuitry is generated by a digital CPU, which was hot enough that it burned Darian’s finger when he happened to touch it, badly enough that he still has a blister a week later! So clearly the CPU was bad– and further testing confirmed it. Continue reading “Sequential Circuits Pro One – CPU upgrade and MIDI retrofit”