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Thread: Teensy 3.5/4.1 Standalone Synthesizer - Trying Modular DYI approach

  1. #1
    Junior Member
    Join Date
    Dec 2020

    Teensy 3.5/4.1 Standalone Synthesizer - Trying Modular DYI approach

    Hello Folks, its been a while.
    I just wanted to share!
    I am finalizing my self-build standalone teensy 3.5 synth utilizing the audio library.
    So thanks for this awesome library, I had some trouble, like a proper DYI project should have, but in the end everything went well and i appreciate the help and documentation.

    What I've done:
    Get a cheap old casio for 5 quit off ebay. strip the keybed.
    Use Teensy 35 and Audio-Shield.
    Use 2 MCP23017 to expand digital i/o.
    Use 4 74HC4051 Muxes to expand analog ins.
    Use 74HC14 and a 6n138 for MIDI IN/THRU/OUT circuit.

    Create a 3 Oscillator + noise audio stream with multiple modulation capabilities:
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    Including volume ADSR, pitch and filter modulation with optional second modulation ADSR.
    3 LFO for modulation (pitch, filter, VCA).
    Ring modulator.
    Octave switch (individual octaves available for 2nd and 3rd oscillator).
    Reverb and Delay FX section.
    Implemented MIDI keyboard output / external MIDI controllability (eg. for sequencer).
    Tempo Tap/ Sync to MIDI.

    For all of this i designed PCBs (unfortunately in the process my pc crashed. I'm now in revision/recreation process) and the Case (frickin pain , to be revised too).
    Revision should hold a polyphonic version and a korg minilogue - like oscillsocope as well because i think its hot and the T41 can handle it . MCP23017 get updated to the SPI versions since i was getting quite a lot of latency with the i2c. I will also shift some of the analog inputs to some MCP3008s also SPI.

    When revising the whole thing i am trying to get the design modular. So when using my pcbs one can hook up all of the stuff i did (mixer / ADSR / FX sections etc.) but could also get a smaller version (eg without keys, or without FX). And also reuse analog inputs to do other things than what i intended.

    However, here it is dear community!
    What i want to say is: if your interested in something like this -> i am revising everything and after proper BOM calculation and reordering of a couple of PCBs i am willing to build a couple of em and make them available.
    I will also put the stuff up on my git after redoing it. So youre welcome to try it yourself and develop / get in touch if you're trying something similar and have/need some experience!
    In any case i am happy as hell and it turned out better than i expected

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  2. #2
    Senior Member
    Join Date
    Sep 2020
    Lovely machine!

  3. #3
    Senior Member fdaniels's Avatar
    Join Date
    Oct 2020
    Ostwestfalen, Germany
    Congratulations, looks great! Whats that fader for?

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