The J2B Synthesizer was developed from the Atmegatron music synthesizer by Soulsby Synthesizers. This design appealed to Elektor designer Clemens Valens so much, that he had to do something with it. The J2B Synthesizer is a port of the open-source sound-generator firmware in the Atmegatron, to firmware which runs on an LPC1347, a 32-bit ARM Cortex-M3. And of course, this more powerful microcontroller offers more functionality than what is possible with the simpler ATmega328, which is in the Atmegatron.
8 rotary encoders control the J2B Synthesizer. Just as with the Atmegatron, the J2B Synthesizer has a red mode and a green mode, in which the rotary encoders set different parameters, indicated by the bi-color LED on the right. As is customary with a synthesizer, it has MIDI-in and MIDI-out. Although the synthesizer does not send MIDI-notes, it can receive MIDI CC-data end therefore can – in addition to a MIDI-keyboard – be controlled via a sequencer or computer.
The ‘programming’ of another/new firmware (there are now four different versions available and a fifth is a work in progress) is very simple:
- Connect the synth via USB to a Windows PC, while you continue to press the red/green mode button.
- Windows will automatically recognize a USB storage medium of 64 KB, containing the file ‘firmware.bin’ (visible via the Windows file explorer.
- Delete this file.
- Copy the new .bin file to the USB medium.
- Restart the synthesizer. Done!
The open-source firmware is available from www.elektormagazine.nl/magazine/elektor-201501/27508. This gives you the opportunity to add features yourself and, for example, have two synthesizers cooperate with each other for all kinds of harmonies and inter-modulations. Even implementing other algorithms for the generation of sound are among the possibilities. The necessary development environment for the Cortex M3,LPCXpresso, is free.
Apart from the fact that it is simply fun to make music, you can create a surprising number of different sounds with the J2B Synthesizer. Even a nice Dubstep drop can be produced with the correct settings. If you have some familiarity with synthesizers, then you will have mastered the J2B Synthesizer in no time. But even if you are still ‘new’, the J2B Synthesizer can be quickly understood when you turn its knobs. It is a light-weight synth, which is very conveniently powered via a mini-USB connection from a phone charger or something similar. It is also possible to connect headphones directly to the output, so that you will not drive your house mates completely crazy with the bleeps and squeaks.
The synthesizer is built professionally, especially for Elektor by Business Partner Eurocircuits and is only available from the Elektor Store.
You can find some example sounds and gain an impression of its operation here: https://youtu.be/rwNBSdC3ZqA
- Monophonic 9-bit synthesizer
- 32 wave shapes + freely definable
- 15 filter types
- 2 envelope generators
- LFO with 16 wave shapes
- Arpeggio for 15 patterns
- 16 patch memories
- 6 live controls
- Patch save and load via MIDI
- NXP LPC1347 32-bit ARM Cortex-M3 microcontroller
- 2 output channels
- Open-source & open-hardware design
- The PCB, manufactured by Eurocircuits: www.elektor.nl/j2b-synthesizer-140182-3.
- The J2B Synthesizer is a professionally built and tested module by Eurocircuits : www.elektor.nl/j2b-synthesizer
- A suitable enclosure: www.elektor.nl/case-for-j2b-synthesizer-140182-92.
- Open-source firmware: www.elektormagazine.nl/magazine/elektor-201501/27508.
- Instructions for updating the firmware: www.elektor-labs.com/contribution/how-to-change-firmware.14503.html.
- Project description (background): www.elektor-labs.com/project/j2b-synthesizer-140182.14137.html.
- LPCXpresso development environment: www.lpcware.com/lpcxpresso.
- Atmegatron Librarian Software: http://soulsbysynths.com/atmegatron-downloads.