Patrick Cowley Sequential Circuits Pro-One synthesizer + Roland TR-808 refurbished by Tone Tweakers

video upload by tonetweakers

"We recently acquired Patrick Cowley’s Sequential Pro-One. We meticulously refurbished it just like we refurbish all the similar vintage synths we sell on our website. We also added the MTG turbo CPU update and MIDI retrofit. We didn’t want to drill holes in the back panel, so we ran an Ethernet cable out of the cable slot in the back to plug into a small external midi connector box. This instrument is now part of the incomparable collection of gear at The Synth Sanctuary electronic music studio in NYC. Track programmed by @jaywires (who you should follow), who will be recording a lot with this classic instrument in January of 2023, if all goes as planned. Buy vintage synths that work like new at tonetweakers.com and please sign up for our newsletters while you’re there. Thanks!"

Tone Tweakers on Reverb | Tone Tweakers on Ebay

Sequential Circuits Pro-One SN 5573

Note: Auction links are affiliate links for which the site may be compensated.

via this auction

"Great working pro one. Nice keyboard (j-Wire). Has some scratches and dings, check the pictures.
Fully working properly.

MTG TURBO + Midi is a huge boost to this unit. All the original features, and all the original analog circuitry plus the following:

Check out music technologies group dot com
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.
Firmware update (�re-flashing�) over MIDI (using MIDIOX or similar).
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.
This unit also includes a 3 prong power supply and a ground loop fix. (look into Pro One hum grounding mod, the units have some issues with that for some people).
All mods professionally installed and are done with connectors, so the voice board can be removed for any future service."

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Sequential Circuits Pro One (MTG Turbo CPU MIDI Mod) SN 2419

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via SYNTH CITY Reverb

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"Here we have Sequential's classic flagship monosynth! A dual oscillator beast with arpeggiator, the Curtis filter, sequencer, and a simple but powerful modulation matrix. The Pro One is well known for its sound and has been used by countless musicians since its release.

This Pro One was just serviced, keybed assembly cleaned and rebuilt, new CPU and socket installed along with the MTG Turbo Midi upgrade kit."

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Sequential Circuits Pro One SN 1716 with MTG Turbo CPU + MIDI

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via this auction

"Huge bass, leads, effects, with cool cross mod section that only a Pro One has. Similar to the P5 but has it's own unique sound. This Pro One is fully functional & in excellent cosmetic condition for it's age, J-wire keyboard and has the MTG Turbo CPU & MIDI retrofit fitted which turns it into a beast and integrates perfectly with any computer / midi based set-up. Really nice clean shape on the front, overall quite clean. Don't miss out on this monophonic analog classic!"

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Sequential Circuits Pro One Synthesizer Turbo CPU MIDI + CV

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via this auction

"This amazing synth is in great shape for it's age and includes the Music Technologies Group Turbo CPU, MIDI and CV upgrade! Professionally installed.

Everything works perfectly. There is a slight mechanical noise on the lowest key when pressed but it doesn't effect the triggering. The filter caps were upgraded to polystyrene for stability and superior sound.

The MTG Turbo upgrade includes the following:

musictechnologiesgroup.com

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. 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 (Beta) For the handy DIYers, add a tiny MCP4728 chip to the v2.00 MIDI board (soon to be available pre-installed as well) and 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!?"

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Sequential Circuits Pro One Synthesizer with MTG Turbo

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via this auction

"Sequential Circuits Pro One Analog Synthesizer (J-Wire Version)
Installed with "MTG Turbo CPU + MIDI + CV."

Midi Functionality. Inputs Midi, Sends Midi Note Data + Data from the Arpeggiator and Sequencer. + MIDI Through
Also receives MIDI CC#

MIDI CC Control Numbers
CC# 1 - Pro One Filter Cutoff
CC#71 - Pro One Osc A Pitch
+
& MTG Kit LFO2
Receives MIDI Modulation Wheel to control LFO2 (depth/amount)
LFO2 -> Filter Cutoff
CC#76 - LFO2 Speed
CC#78 - LFO2 Waveform Shape
CC#79 - LFO2 Quantize On/Off
CC#80 - LFO2 Key Sync

Read about the full implementation here"

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MTG R100 Builder – Kawai R100 EPROM Builder Software & Expander Switcher

via Music Technologies Group

"This software will enable you to create your own custom EPROMs (BIN files) for the Kawai R100 legendary 12-bit drum machine/rhythm composer.

In a nutshell you collect/create a bunch of WAV files, one for each of the 24 instruments and then this software compiles and converts them into the compressed Kawai format. It’s been a pretty big undertaking, starting with the dissection of the Kawai ASICs. I will eventually include a User Manual and a bunch of WAV and BIN files to get you started.

Your WAV files should each be:

Mono (1 track)
Sample rate of 31.25kHz (you can resample easily in Audacity or similar)
16-bit linear PCM (standard WAV)
Should fit within the sample space of the pad you are targeting."

Kawai R-100 EPROM 3x Expander Switcher

"These are new "SoundSwitcher" boards for the Kawai R100. Each board includes copies of all 3 of the Kawai Factory ROMs that were released. (It is my understanding that these are the ROMs for the R100/R50, R50e and a jazz/fusion one.) You get triple the sounds and it's awesome.

Set-by-step instructions with photos are included. Don't miss this chance to fit your R100 with all the sounds made for it. The circuit board is silkscreened with the signal names, so all you circuit benders out there can bend your drum machine without messing with a fine vintage instrument."

Sequential Circuits Pro One CPU/MIDI Upgrade

More pics and some notes on XBS. The kit is from Music Technologies Group.

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Kawai R-100 EPROM 3x Expander Switcher with ALL 3 R-series ROMs

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via this auction

"This is a fully functional rare "SoundSwitcher" board for the Kawai R100 (may work on others like R50 but don't know for sure). It includes copies of all 3 of the Kawai Factory ROMs that were released. It is my understanding that these are the ROMs for the R50, R50e and R100. In any event you get triple the sounds and it's awesome. Search the web to learn more about it. I don't have any instructions but I do have a ton of pictures of how it is installed if you aren't familiar with this mod. Don't miss this chance to fit your R100 with all the sounds made for it.

It's the purple board shown in the photos above. The circuit board is silkscreened with the signal names, so all you circuit benders out there can bend your drum machine without messing with a fine vintage instrument. Also note that the photos show the Kawai Mask ROMs. This kit includes EPROMs, but they are functionally identical."

New MTG Kawai R100 ROM Swticher Expansion Boards

This is a follow up to this post.  You'll find full details on the Music Technologies Group blog.

"As you may have seen in my previous post, my Kawai R-100 Drum Machine came with a 3-EPROM 'soundswitcher'. Since this is no longer available, I thought I would make my own. It’s not an exact clone of the Drumware Inc board...

I did a 2-layer board compared to the old Drumware single-layer board that was probably taped up by hand. In fact this is how I used to make SRAM memory expansions myself in the late 80′s. I even advertised them in the back pages of Polyphony magazine (for JX3P, OB DX, Polysix and a few others)."

Note there are only a few boards available, so if you are interested click through sooner than later.

Yamaha DX7 Blue Backlit LCD kit

via this auction
"This kit replaces the old non-backlit LCD on a Yamaha DX7 with a beautiful new BLUE one with long-lasting LED backlight.

Blue LCDs in this exact size that fit the DX7 are extremely hard to find, especially blue. Limited supply ( I have a couple more).

Easy to install!
Only one solder connection required.
Step-by-step instructions.
With original Yamaha LCD connector so no mistakes!!
The back-light is current-limited to protect the DX7 power supply from working too hard.
Replaces original non-backlit or later green backlit LCDs on original DX7.
NOTE: Blue LEDs not included but available as a separate auction (combined shipping available).

See my other auctions for other great synth parts and upgrades including the DX7 Special Edition ROM (SER) and lots of great Pro One upgrades."

Music Technologies Sequential Circuits Pro One Turbo CPU

via this auction "This is a newly developed (modern) replacement CPU for the Sequential Circuits Pro One 8021. Bring that old Pro One back to life or simply have a spare for the "unobtanium" 8021.

MTG Turbo CPU 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 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 my CPU+MIDI eBay ad."

More info at Music Technologies Group Blog
Tiny pics. If anyone has a bigger one, feel free to comment or send it in.

Genovation Keypad MIDI Patch Changer

Programmable MIDI Preset Keypad via Genovation
Update via Grant B in the comments: "www.musictechnologiesgroup.com is the new home for this device."

"The Genovation MIDI Patch Changer is the perfect solution when you need to control MIDI presets for one or more devices, but you don't want to use a giant keyboard controller, MIDI footswitch or MIDI pedalboard. The MIDI Patch Changer has all the features you'd expect in a full-featured patch changing controller.

* Programmable, compact and easy to use.
* Manual mode lets you send Program Change as well as optional Bank Select MSB and LSB.
* Preset performance mode sends program-change-per-MIDI-channel as well as Bank Select on all 16 channels simultaneously -- per preset.
* Send 16 bytes of MIDI data of your choice (anything!) per Preset.
* 1 x 16 super-twist back-lit LCD.
* Detachable cabling for 5-pin DIN MIDI and USB-MIDI.
* "Flash" memory holds patches and config data.
* Firmware upgradeable (using MIDIOX or similar).
* 1 year warranty.

Dimension: 15.5cm x 9.6cm x 3.5cm (6.1" x 3.75" x 1.5")
Weight: 0.3 kg (0.65 lbs)
Manual Mode: For changing patches on the fly, you can select your MIDI Channel, optional Bank Selects* and Patch Change value(s).

The values can be typed in on the number pad or use the up/down keys to scroll through presets. When the patch number rolls over 0, enabled bank selects are automatically incremented or decremented. Move through hundreds of patches with ease.

The unit allows you to send the MIDI commands instantly as-you-type-them or prepare them first and execute them later with one keypress.

Bank Selects can be quickly disabled/muted when not needed or desired.

16 bytes of Arbitrary MIDI Data can be used for sending controller data, system exclusive, RPN, NRPN or anything you need.

When power is interrupted, the unit remembers exactly where you left off.

* MIDI Controller values 0 and 32.
Preset Mode: You can configure 100 performance presets each containing:

* 16x (one for each MIDI channel) bank MSB, bank LSB, patch change.
* 16 bytes of arbitray MIDI data -- send what you want.
* Name for the LCD.
* Sys Ex implementation allows for setting up presets on a PC.

Extras: You can upgrade the flash firmware so that your MIDI Patch Changer is always up to date.

Free Windows PC software for creating the Sys Ex files is available."

MTG Pro One Turbo CPU+MIDI+CV - LFO2 MIDI Filter Cutoff S&H

YouTube via thisfear | August 21, 2010

"LFO2 is being applied this time to the Filter Cutoff. Reonance is also controlled over MIDI here. Demo shows sample and hold stuff. Sorry for the audio/video -- it's just a flipshare cam with an internal mic.

Fast-forward to 2:00 for typical usage (the good stuff)."

MTG Pro One Turbo CPU+MIDI+CV - LFO2 MIDI Pitch Synthi Drums

thisfear | August 21, 2010

"Falling ramp LFO2 synced to key down provides a simple synth drum effect. Sorry for the audio/video -- it's just a flipshare cam with an internal mic."

MTG Pro One Turbo CPU+MIDI+CV - LFO2 MIDI Pitch Modulation

thisfear | August 21, 2010

"New LFO2 modulating the osc pitch. LFO2 is controlled using MIDI. Video shows various waveforms and stuff. Sorry for the audio/video -- it's just a flipshare cam with an internal mic."

MTG Pro One Turbo CPU+MIDI+CV - MIDI Pitch Bend

thisfear | August 21, 2010

"Simple pitch bend demo showing the CV option at work. Sorry for the audio/video -- it's just a flipshare cam with an internal mic."

Axio - Alternative MIDI Control Surface

YouTube via thisfear.

via GB "I designed the electronics and firmware for the chording keyboard in this alternative MIDI controller in the early 90's. It was made using a set of Yamaha DX7 key contacts. These contacts have both make and break contacts which allow for velocity sensing. The firmware was done in 8031 assembler and the source code is posted on my website, www.MusicTechnologiesGroup.com. The project was presented at various conferences and symposiums around the world."
Note the ribbon controller and additional buttons on the joystick.