First testing in its new home.....

video upload by Craig Barnes

"Finally transferred the polysynth from the work bench to the CME UF-70 chassis. it's a tight squeeze, but it all goes in, still a few bits and pieces to do, put a power socket on the back fit the mains and code up a few improvements and bug fixes."

4 quick sound patches for Craig Barnes new synth

video upload by Craig Barnes

"Sound design is one of the hardest parts of building a synth. So as this design contains similar elements to the P5 with polymod, I just added some sounds from the patch book. They are not exact of course."

Unison test of the 8 voice polysynth

video upload by Craig Barnes

"I finally fixed a lot of issues on the filter board with signal routing, a couple of bad connections, a lost ground, some signal inversions etc. All of these hsve now been addressed and I can concentrate on the software side of the synth to fix and implement features."

Finally a working polyphonic MIDI to CV converter with auto tune.

video upload by Craig Barnes

"I've been working on this polyphonic MIDI to CV converter for about 2 years. I've built several other polyphonic MIDI to CV devices, but I needed an 8 note 16 bit device for accuracy. So previously signals like modulation, bend, interval, detune were all generated on separate CV lines. This converter combines all signals onto a single wire for each VCO and filter. So in total there are 24 CVs generated, 8 gates, 8 triggers, 8 velocity CV's, plus 8 spare CV lines if needed.

The Teensy has a feedback loop from each VCO via a 16 way mux chip and during auto tune each VCO in turn is fed into the Teensy and the frequency of 8 notes from each VCO is sampled and corrected against the correct frequency. The difference is then stored in a table and the remaining 120 corrections are extrapolated from the 8 samples. These are then stored into the SD card and reloaded at boot time.

It accepts 5 pin DIN MIDI and usb MIDI or it can act as a MIDI host to a usb keyboard. I hope to make it the basis of an 8 note analogue polysynth that actually stays in tune.

Functions are controllable over MIDI

https://github.com/craigyjp/16bit-8-n..."

Akai AX-80 editor in action.

video upload by Craig Barnes

"Completed Akai AX-80 editor, can store upto 5 sysex banks sent from the synth or pc etc."

AX-80 editor for Tauntek equipped AX-80 synths.

video upload by Craig Barnes

"I started building this midi controller for the AX-80, all 45 controls are presented with buttons and LEDs for the switch functions. Pots for the 0-99 controls. It will have 999 patch memories and names and can be used as a master for the AX-80 which means you don't store any sounds on the AX and the editor is in charge. Or normal mode where it just edits parameters. It also acts as a usb to MIDI converter so you can play the AX over USB from your DAW. I've also mapped CC 7 for volume to CC 96 (VCA level) to act as a volume control."

A Bit More - starting to come together

video upload by Craig Barnes

"This is my 8 voice bi-timbral poly synth based loosely on the Crumar Bit series of polysynths. The 8 DCOs are sent note on/off messages over midi on individual midi channels from the controller board. Common commands for octave shift etc are send on channels 1 & 2 for each half of the synth.Just testing the polyphonic control for Poly 1, 2, solo and unison."

Crumar BIT DCO clone with added functionality

video upload by Craig Barnes

"This dual DCO is based on the counter/resistor ladder technique used in the Crumar Bit series of polyphonic synthesizers, the 8253c triple counter has been replaced by a Waveshare Zero RP2040 based SOC. This allows the Waveshare to receive MIDI and calculate portamento etc. The only thing I want to add is an interval for DCO2 to set things like 5ths up in the DCO pair. Each DCO currently has 4 waveforms, Saw, PWM, Triangle and SUB. Although I might reduce that down by removing a triangle and SUB from either side. It was designed as a DCO core for a monosynth or a poly depending on needs."

PolyKit DUO 6 Voice DIY Poly Synth by Craig Barnes

video uploads by Craig Barnes

"PolyKit DUO first tests as a 6 voice poly. some bugs to iron ouThis is the first test of the basic functions of this 16 voice DCO based analogue synthesizer. It will be bi-timbral when complete with upper and lower sounds with 8 voices in each, dual, split and single modes. Still a lot more work to be done. t in the software around the portamento controls, but other than that it's almost there.

https://github.com/craigyjp/PolyKit-D..."

Playlist:
PolyKit DUO first tests as a 6 voice poly
Bi-timbral PolyKit 16 updates

Second phase of the PolyKit construction was to create the bi-timbral software so it can create, save and load two sounds at once. so far so good with some spurious aftertouch in there.

PolyKit 16 first fully polyphonic test

PolyKit DUO preliminary demo with only one filter installed.

Preliminary testing of a single voice as I have no more AS3372E chips and they seem to be lost in the mail from Portugal. Had a few issues with wiring, always the way when you do two voices on a board at once. Filter 1 & 2 EG outputs were swapped. And EG level for voice 2 had two pins swapped on the 4053 switch between velocity and full level. Need to debug some more but so far I'm happy.

PolyKit 16, a bi-timbral 16 voice dual DCO Polysynth.

This is a short demo of a small selection of sounds produced by the PolyKit 16 programmable Polysynth. It is based on the PolyKit DCO by Jan Knipper and has been expanded from 6 note polyphonic to 16 with dual DCOs instead of single, additional sub and triangle outputs and dual LFOs and a noise source per bank of 8 voices. Still more work to do on the programming like trying to create patches as well as presets.

Poly6 Teensy 3.6 based Polysynth with patch memory

video upload by Craig Barnes

"Teensy-Poly6

This is a polyphonic synth forked from albnys/TeensyPoly6 converted into a 2U 19" rack.

https://github.com/craigyjp/TeensyPoly6

The analogue interface now uses 6 MUX chips to read the pots and switches so there is no need to connect top the top or underneath of the Teensy 3.6 for the extra analogue inputs required. It runs smoother now as well.

The schematics are upto date now with the latest mux changes.

The synth is built using a teensy 3.6 overclocked to 192Mhz and is programmed in Arduino IDE using the teensy audio library.

Easily upgrade to a T4.1 or even a T4.0 as very few connections are required now. Increase of polyphony is probably available with a T4.x.

How it sounds in the original keyboard form, this sound engine is unchanged.

• Homemade Polyphonic Synthesizer! [posted here]

Triple VCOs with octave +/- shift.

Osc A with SAW, PULSE (PWM) and TRIANGLE waves, plus SUB and Crossmod

Osc B with SAW, PULSE (PWM) and TRIANGLE waves, plus tuning, oct +/-

Osc C with 28 waves, plus tuning, oct +/-

LP/BP filter with resonance and env +/- for A/D/R

LFO with SAW, TRIANGLE and SAMPLE & HOLD waves

Modulation destinations for FM. TM and AM

LFO attack, decay and sustain with depth control

PWM LFO with rate and depth

Digital reverb with size and mix amount

Digital delay with time and mix amount

Programmable ranges for Pitch, Modulation and Aftertouch

Mono, Poly and Unison (two voices) modes, Unison detune ranges

Note priorities for Mono and Unison modes, Top, Bottom, Last.

MIDI modulation, aftertouch, CC messages for controls, channel change, pitchbend.

999 memories with storage of all front panel controls except volume.

MIDI In, Out, Thru"

Sequential Prophet 600 clone on proto board with Gligli upgrade

video upload by Craig Barnes

"A complete clone of a Sequential Prophet 600 built into a CME UF60 case, push buttons were used instead of the membrane. AS3372E chips were used instead of the standard AS3372 which are expensive and hard to find. Total cost around 600 euros and a month to build on and off."

Moog Source based clone controlled by Teensy 3.6

video upload by Craig Barnes

"I love the Moog Source but really cannot justify over £2000 to buy one without MIDI etc. So I made a monosynth based on the style of the Source, I replaced all the button/value selections with actual pots to make editing simpler. I added another LFO to control the PW of each oscillator with depth controls. The ladder filter is from the MemoryMoog. It stores 999 patches and has MIDI and CV inputs. Note priorities etc. The envelopes are Electric Druid EnvGen8C devices so I have added log/lin envelopes and looping modes."

More Moog Source clone sounds

video upload by Craig Barnes

"This is my attempt at cloning the classic Moog Source but also bringing it upto date. I built this synth over a year ago before the war started. I recently took it off the shelf and tried to remember how exactly I wired it up as I made very few notes of the schematics, most of it was on the fly or from tried and tested methods I had in my head. But I think I got about 95% of it loaded into GitHub now and I made a few changes along the way. I updated the software and added more features over MIDI such as aftertouch, midi clock sync etc. it sounds better in the flesh than recorded on my phone but currently my studio is out of action due to Putin's ongoing effort to destroy this country. I hope you like it and the other synths on my channel, I'm not much of a player so relying on the arp from a keystep whilst filming with my phone. The last sound "Thump Bass" is an example of the repeating envelopes for the filter and amp.

https://github.com/craigyjp/Moog-Sour..."

VCDO based Polysynth in a Crumar Stratus case

video upload by Craig Barnes

"A 6 note polysynth design that I have been building on and off for about 3 years since i had the idea. I gutted an old Stratus as I got it very cheap and the original idea was to only replace the organ generation circuits with real VCO's or DCO's to feed the Stratus CEM filters etc. But as it developed I ended up replacing more and more of the Stratus with my own designs or interpretations of designs I've found on the web. It switched between CEM3340 VCO's an Electric Druid VCDO1 chips, eventually settling on the VCDO1 chips even though the waves are only 8 bit, its very PPGish.

The specs are as follows.

Dual Electric Druid VCDO1 oscillators with modified firmware for new waveforms and performance.
Multipole filters similar to the Shruthi design but using the CEM3320 and pole mixing. 16 states, resonance, key tracking, EG depth & invert and looping.
LFO with 16 waveforms, slope and delay, depth and multiple destinations. Electric Druid TAPLFO3.
White Noise source based on the Electric Druid Noise 2
3x EG's per voice, Pitch, Filter and Amplifier, switchable velocity on each EG, Electric Druid EnvGEN8c.
Bit Crush on the waveforms
Poly/Unison modes
999 memory locations
MIDI and CV in/outs and can be used to drive CV based equipment"

Korg DW6000 editor built into the DW6000

video upload by Craig Barnes

"This is a Teensy 4.1 based sysex editor for the Korg DW6000, it can hold 999 patches and update the DW on each patch selection. Sysex params also have corresponding CC numbers so it is easily controlled by a DAW or other external controller. It can also receive and send MIDI over USB to all connection to a PC or MAC without a MIDI interface.

It can receive sysex patches over MIDI and these can be saved in the editor or synth.

In master mode the editor is in charge and simply sends new patch data every time a program change is made. The synth memories are irrelevant at this point, but it also allows you to build a bank of sounds in the synth if you wish as any of the patch data sent from the editor can be saved in a synth memory location.

in slave mode the editor simply sends a program change to the synth and recalls a patch. You can edit the patch with the editor and save it in the synth, but it will not be in sync with the editor memories 1-64.

You can send individual or all the patches of the synth out as sysex messages from the menu.

Any suggestions I will consider implementing if possible.

Also a copy of the factory patches are stored onboard and you can send these at anytime to the DW6000 to factory initialise its sounds.

Also you can send all of your patches from the DW6000 to the editor to bring it up to sync with your synth, probably the best thing to do. The only caveat is you will have no patch names as the DW6000 does not hold that data, so you will have to rename the patches if you require names.

Schematics and code can be found here.

https://github.com/craigyjp/Korg-DW60..."