[sdiy] Who apart from me things the whole MIDI board needs replacing ?

Sean Ellis tensiontype at hotmail.com
Thu Jan 27 13:08:24 CET 2022


Let me rephrase: in the circuit as shown will the MCU will get a signal no matter if it's a midi cable or a gate signal on a mono cable? Just seems like it would be easy to make a dual use input.

________________________________
From: Roman Sowa <modular at go2.pl>
Sent: Thursday, 27 January 2022 11:55 AM
To: Sean Ellis <tensiontype at hotmail.com>; synth-diy at synth-diy.org <synth-diy at synth-diy.org>
Subject: Re: [sdiy] Who apart from me things the whole MIDI board needs replacing ?

Optocouplers are commonly used in inputs of industrial controllers of
any kind.
At least they were for decades. Not so much anymore when everything is
going ethernet

Roman

W dniu 2022-01-27 o 11:36, Sean Ellis pisze:
> As an aside, with the circuit posted below could that midi input also be
> used for a gate input with correct protection? Seems like the diodes
> will do the job as long as it's a mono cable into stereo jack.
>
> ------------------------------------------------------------------------
> *From:* Synth-diy <synth-diy-bounces at synth-diy.org> on behalf of Roman
> Sowa <modular at go2.pl>
> *Sent:* Thursday, 27 January 2022 10:49 AM
> *To:* synth-diy at synth-diy.org <synth-diy at synth-diy.org>
> *Subject:* Re: [sdiy] Who apart from me things the whole MIDI board
> needs replacing ?
> There are also optocouplers with dual LEDs in reverse, so polarity
> doesn't matter without hassle of adding diodes. For example APCL214,
> which I've used in my MIDI2CV converters. Not only it provided
> mistake-free wiring, but was also smaller than typical SOP5 optocoupler.
>
> Roman
>
> W dniu 2022-01-26 o 20:04, Sean Ellis via Synth-diy pisze:
>> Quite a few modules do it:
>> https://raw.githubusercontent.com/jakplugg/Neutron-Sound-Dust-of-Time/master/schematic.pdf
> <https://raw.githubusercontent.com/jakplugg/Neutron-Sound-Dust-of-Time/master/schematic.pdf>
>
>> <https://raw.githubusercontent.com/jakplugg/Neutron-Sound-Dust-of-Time/master/schematic.pdf
> <https://raw.githubusercontent.com/jakplugg/Neutron-Sound-Dust-of-Time/master/schematic.pdf>>
>>
>>
>> ------------------------------------------------------------------------
>> *From:* Synth-diy <synth-diy-bounces at synth-diy.org> on behalf of Quincas
>> Moreira via Synth-diy <synth-diy at synth-diy.org>
>> *Sent:* Wednesday, 26 January 2022 3:11 PM
>> *To:* Mattias Rickardsson <mr at analogue.org>
>> *Cc:* Synth DIY <synth-diy at synth-diy.org>
>> *Subject:* Re: [sdiy] Who apart from me things the whole MIDI board
>> needs replacing ?
>> Matias, the Tukra by Tesseract does the same. Works with both standards
>> for the input and has selectable output.
>> I appreciate the nostalgic love for Din connectors but they seriously
>> limit the size and shape of the devices. I like how things are skinny
>> these days… And yes, while the standard chose a smaller barrel, this was
>> indeed done too late when already all manufacturers are using 3.5mm.
>> They should have stuck to that and just chosen one polarity to be the
>> standard  IMO.
>> BTW I’ve been using 3.5mm trs MIDI for nearly a decade myself and have
>> never encountered a ground loop issue.
>>
>> On Wed 26 Jan 2022 at 4:57 Mattias Rickardsson <mr at analogue.org
>> <mailto:mr at analogue.org <mailto:mr at analogue.org>>> wrote:
>>
>>     <grant at musictechnologiesgroup.com
>>     <mailto:grant at musictechnologiesgroup.com
> <mailto:grant at musictechnologiesgroup.com>>> skrev:
>>
>>         Hey, it only took them a decade or so to include a messed up
>>         standard for 1/8" TRS connectors.
>>
>>
>>     But the MIDI standard for TRS jacks ended up using 2.5 mm jacks, not
>>     3.5 mm (1/8"). Just to avoid confusion. (-:
>>
>>     3.5 mm was already the de-facto standard by then. But half of the
>>     manufacturers ended up using one polarity and the other half chose
>>     the other, which potentially makes MIDI devices incompatible, unless
>>     special cables/adapters are at hand.
>>
>>     In Elektron's Model series of instruments we implemented the TRS
>>     MIDI In to accept any polarity (passively, using diodes!), and a
>>     setting in the UI chooses between the two polarities for the TRS
>>     MIDI Out. Has this been done anywhere else? I've always felt that it
>>     perhaps should be published as an official application note, a
>>     suggested implementation superpower for other manufacturers to pick
>>     up. :-)
>>
>>     /mr
>>
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>> Quincas Moreira
>> Director | QMA
>> mobile: 5534988825 <tel:5534988825>
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