Turbo CPU

The MTG Pro One Turbo replacement CPU Module is a drop-in replacement microcontroller for the Sequential Circuits Pro One's 8021 CPU (AKA P8021/8021H/P8021H).

Features:

• Plug-n-Play! No soldering required!
• Supports the original functionality including the sequencer and arpeggiator.
• Each sequence can be up to 256 steps (compared to total of 40 steps on the original).
• Sequences are retained in memory even after power-down. The CPU module does not use a battery.
• Power-on settable parameters for clock start mode, arpeggio up/down end notes, arpeggio down mode and arpeggio gate time.
• Sequence Tie mode allows for a variety of note lengths.
• Sequence End mode lets you chain the two sequences.
• Optional: If you want to make your own MIDI interface, instructions are in the manual. If you want MIDI hardware included, see CPU+MIDI.

Turbo CPU + MIDI

The above plus a MIDI In/Out interface board that adds the following features*:

• Firmware update (“re-flashing”) over MIDI (using MIDIOX or similar).
• Settable MIDI channel.
• Receive MIDI note data.
• Monophonic MIDI output of arpeggiator and sequencer data.
• Polyphonic MIDI output of keyboard data.
• Arpeggiator and sequencer sync-able to MIDI Sync In (settable clock rate).
• Load/Save sequence data over MIDI.
• MIDI In, MIDI Out and optional MIDI Thru.
• Optional MIDI In/Out activity LEDs.
• Pads for optional DAC chip (see CV option below).
• Soldering and installation are required for MIDI.

Turbo CPU + MIDI + CV  

For the handy DIYers, add a tiny MCP4728 chip to the v2.00 MIDI board (soon to be available pre-installed as well) and massive analog control over MIDI will be yours! Simply connect it via 2 additional wires from the MTG Turbo CPU and then tie into the Pro one using 4 CV wires. No trace cutting or case butchering!

See the firmware and manual(s) below.

• All you need is the MCP4728 chip, some wire and solder.
• Four 12-bit digital-to-analog converters.
• Supports MIDI Pitch Bend receive including setting the range/sensitivity using RPN.
• Control of Filter Cutoff and/or Resonance.
• LFO2 with multiple waveforms (Square, Saw, Triangle, Sine, including Sample & Hold).
• LFO2 range from 0.1Hz to 10Hz (10 seconds/cycle to .1 seconds/cycle).
• ... and more!?

Manual

Also see the Release Notes in the Firmware section below.

USER manual                           (150kB PDF)     Contains preliminary/beta CV operation info.

INSTALLATION manual              (1MB PDF)       Does NOT contain CV install info. See below.

D-I-Y CV Installation manual   (750kB PDF)     Separate CV install info.

Ordering Information

Please note: I am building these by hand for now. Quantities at any given time are limited.

Please order off my eBay page.

Firmware

Please read the Release Notes.

• Version 1.11 : Download SYX file (Current CV Beta)
• Version 1.10 : Download SYX file (Earlier CV Beta)
• Version 1.00 : Download SYX file (Current non-CV)

System
Exclusive
Examples

Some sample .SYX Sys Ex files for reading and writing the settable parameters (zipped). These files are for MIDIOX (or a similar app) but the included text file lists all the commands and you can cut and paste them into your favourite application/tool.

• ProOneSysExExamples.zip : Download ZIP file

• Cantos Music Centre (Canada)
• http://www.analogsynthservice.com (USA)
• Digital Audio Service (Germany)
• http://www.synthwood.com (USA)
• http://www.audiorehab.net (USA)
• http://www.theanaloglab.com (NYC, USA)