Propsynth D - a 6 voice polyphonic synth with Propeller chip
PropB3
Posts: 10
in Propeller 1
Hello,
here is my latest development.
A 6 voice Synth, using the Propeller Chip
bolltone.de/Projekte/PropSynthD/PropSynthD.htmlhttp://
It is a DIY project, included all files/schematics to build the synth.
habe fun
PropB3 / H.Bollig
here is my latest development.
A 6 voice Synth, using the Propeller Chip
bolltone.de/Projekte/PropSynthD/PropSynthD.htmlhttp://
It is a DIY project, included all files/schematics to build the synth.
habe fun
PropB3 / H.Bollig
Comments
bolltone.de/Projekte/PropSynthD/PropSynthD.html
Luckily, schematic and parts list are mostly universal.
Even if you aren't interested in synthesizers or music, you take a look at this project. It is very well done and complete!
NOTE: We can use Google Translate to convert the web page from German to English
PropSynth D
A 6-voice synthesizer with a propeller microcontroller & FV-1
Prototype PropSynth D
Hello to all music enthusiasts.
After the Hammond organ and the String Keyboard simulations based on a Parallax Propeller, the step to build a synthesizer was the logical consequence.
This new development is a classical polyphonic 6-voice synthesizer according to the well-known model: Oscillator-Filter- VCA, also known as subtractive tone generation.
This time I did not want to emulate a very specific synthesizer, but to develop a "normal" sound generator, which cannot do any more than many other synths, - but with a standard processor not developed for this purpose.
Features:
• 2 oscillators per voice / 6-voice polyphony
• 10 Wavetables for the oscillators
• Filter, (4-pole lowpass, 2-pole lowpass / highpass / bandpass) with resonance
• ADSR Generator for filter curve
• ADSR Generator for Amplifier Envelope (VCA)
• LFO for filter modulation
• LFO for Vibrato
• Noise generator
• Various chorus effects
• Hall device
• 3-band EQ
• "Half-analog" operation with potentiometers in a parameter matrix
• Preset memory, 32 programs
• LED display
• Control via MIDI controller
• Stereo outputs
Controlled via MIDI, the propeller is enough for 6-voice polyphony. The mainboard is only 200 * 100mm and contains all components inc. the control elements. The one-sided PCB is easy to build, since only components which are easy to obtain are used, SMD components (which we unfortunately can not do without) are installed via adapter, and with 1.27mm pin spacing can be easily soldered by hand.
But before we get to the nuts and bolts, here are some legal notes:
Disclaimer:
The author accepts no liability or warranty for damages which arise directly or indirectly with the use of this project.
The PropString is intended for private use only. A commercial exploitation of the circuit, software or parts thereof is hereby prohibited.
Here is a sound demo (everything comes from the PropSynth D - no additional effects added)
Jumper
CS81
The Leslie Organ
Flute
Jupiter Strings
DX Piano
Jumpin LFO
MonoPoly
PropString
My wishes, wants and ideas are rising: - (again)!
Originally, this project should be a classic hybrid analog synthesizer, ie digital oscillators and analog filters, etc. A 4-voice model was almost finished, but when I added up the numbers of capacitors, resistors and IC's, I rejected this and devoted myself to the purely digital solution. It was supposed to be a weekend project, and not a life task.
Hardware at the limit :
DSP functions without multipliers, sounds like "Rally Paris - Dakar on a bike" and is actually not possible, and on top of this the propeller can only address 32 KByte. This is not much for firmware, waveforms and memory.
Relief comes in the form of the FV-1 chip. In addition, the propeller runs not at 5MHz but is "overclocked" at 6.4MHz.
Some of the PropString design was used, like the FV-1 effect processor. Controls using potentiometers and switches as with the PropString I found nice to use, but with the number of parameters a large number of controls cannot be avoided.
This time, too, a display, for parameter control, should be used. I decided to use the "Parameter Matrix", a concept consisting of pushbuttons for line selection and potentiometers in the columns (which was very beneficial in the development because new parameters / functions simply fit into free spaces in the matrix).
The Synth can of course be completely remote controlled via MIDI. The whole circuit fits exactly in Hammond 1599-HSGY housing.
Etching - soldering - programming
All the necessary documents for construction cab be found here. Propeller, FV-1 chip are also relatively easy to procure in Germany. The D/A converter is available on EBAY.
What you will need, however, is a burner for I2C-EEPROMS. There are two EEPROMS to burn. A 512 (64Kbyte) for the propeller, and a 32(4Kbyte) for the FV-1 processor. On the internet are many building instructions for simple I2C burners. I used PonnyProg. The required hardware is easy to build, and the software is free.
Wiring diagram: PropSynth Schaltplan.pdf
The complete building instruction: Bauanleitung.zip
Notes and controller assignment: Notes.pdf
Mainboard Mainboard & Control Panel
PCB backside with voltage regulator & wire bridges Parameter matrix
Gordon
Edit - now (April 5) I cannot.
https://web.archive.org/web/20161018021944/http://bolltone.de/Projekte/PropSynthD/PropSynthD.html