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Thread: teensy usb midi to waveblaster

  1. #1
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    teensy usb midi to waveblaster

    Hi

    I have a waveblaster clone daughter card. Back in 90's i used to plug it on my sb16, and then to a monster sound. I'm out of options on my new rig, but still very fond of those old dos games and their midi ost.

    Would it be feasible to interface this board through a teensy to get it to behave like a general midi card?

    I'm shooting a coin in the air there, because I really have no idea where to begin

    I've found the port schematics here http://joska.duckdns.org/db50xg/

  2. #2
    Senior Member PaulStoffregen's Avatar
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    Yes, probably possible, though a long journey on the software side. Whether any old dos games would generate MIDI output in a way that could be passed to USB is a good question. I really don't know much about that, other than the obvious idea to check this first before putting in so much work.

    This project is probably a good starting point for the coding side...

    https://github.com/TeensyAudio/Wavetable-Synthesis

  3. #3
    Senior Member oddson's Avatar
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    Do you just want Teensy to act as a usb MIDI host [edit - I think I meant 'bridge'] running a MIDI-thru sketch?

    If you are then you don't need the optocoupler part of the curcuit as 3.3v-Teensy can souce/sink a 5v TTL input directly. (I think, otherwise a level shifter might be needed but not isolation.)

    If you're trying to get Teensy to do what the the Sound Blaster mother card normally does then it will not be so simple and potentially very difficult.

    Maybe you could be a bit more explicit in what your trying to do.
    Last edited by oddson; 01-04-2018 at 08:16 PM.

  4. #4
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    Quote Originally Posted by PaulStoffregen View Post
    Yes, probably possible, though a long journey on the software side. Whether any old dos games would generate MIDI output in a way that could be passed to USB is a good question. I really don't know much about that, other than the obvious idea to check this first before putting in so much work.

    This project is probably a good starting point for the coding side...

    https://github.com/TeensyAudio/Wavetable-Synthesis
    Thank you for answering. I also got some leads from Vogons forum. I have to think if it's worth the effort, and if its feasible with my current skills

  5. #5
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    Quote Originally Posted by oddson View Post
    Do you just want Teensy to act as a usb MIDI host running a MIDI-thru sketch?

    If you are then you don't need the optocoupler part of the curcuit as 3.3v-Teensy can souce/sink a 5v TTL input directly. (I think, otherwise a level shifter might be needed but not isolation.)

    If you're trying to get Teensy to do what the the Sound Blaster mother card normally does then it will not be so simple and potentially very difficult.

    Maybe you could be a bit more explicit in what your trying to do.
    I am not sure yet. My first idea was to use the teensy to drive the waveblaster, not to behave like a sound blaster (from a DOS point of view). And also using Usb Midi, I'd like to be able to select this new midi device on some emulators like scumm or Dosbox. The bonus part would be to provide my 12 year old boy with a new musical source to show him how good these boards can sound, in simple media player or in a DAW software (he plays music)

    I'm a software guy, so this part does not scare me (and i have the feeling that it is more or less just a pass though with TTL like the TeensyMidi sample - the hard work is already done)
    But I'm still a beginner on electronics, and the PSU part of this waveblaster is on a whole new level for me (maybe I'll use a PC PSU for 5/-12V); not to mention that I only have one waveblaster, I have it since 1992 and I don't want to fry it

  6. #6
    Senior Member oddson's Avatar
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    You could build the circuit as-is and you would be able to plug any MIDI (DIN) source into it and it should work as advertised.

    The Teensy part would then be a USB to DIN MIDI translator and should let you send usbMIDI to the card. You would need to build the MIDI out 'circuit' for it (which consists or two current limiting resistors and a DIN socket). https://www.pjrc.com/teensy/td_libs_MIDI.html

    But if you ONLY want to send usbMIDI to the board then the Teensy-to-Blaster connection doesn't need the optoisolator and (I'm pretty sure but not qualified to say with certainty) the 3.3 volt Teensy output would be sufficient to read as HIGH on the Rx of the card (5 volt TTL).

    So you'd only need the power filter and reset features of the schematic and a 12/5 volt power supply.
    Click image for larger version. 

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    The Teensy would share the 5 volt power supply (which means you'd need to understand the external power page).

    You're unlikely to fry the Blaster with anything coming from the Teensy as it only outputs 3.3 volts.

    The sketch would then just send the same MIDI as it receives (MIDI Thru).

  7. #7
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    Wow thank you very much for your detailed answer, I will look into it !

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