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It boggles the mind companies would rather have converter plugs (for their inputs only) instead of adding 2 or 3 diodes.</div>
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<div id="divRplyFwdMsg" dir="ltr"><span style="font-family: Calibri, sans-serif; font-size: 11pt; color: rgb(0, 0, 0);"><b>From:</b> Synth-diy <synth-diy-bounces@synth-diy.org> on behalf of Andrei Kudryavtsev via Synth-diy <synth-diy@synth-diy.org><br>
<b>Sent:</b> Thursday, 27 June 2024 8:55 PM<br>
<b>To:</b> Martin Klang <mars@pingdynasty.com><br>
<b>Cc:</b> Synth-diy <synth-diy-bounces@synth-diy.org>; Mattias Rickardsson <mr@analogue.org>; synth-diy@synth-diy.org <synth-diy@synth-diy.org><br>
<b>Subject:</b> Re: [sdiy] MIDI cable impedance and MIDI In ESD protection?</span>
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<div style="direction: ltr;">Speaking of TRS mess, found this one in the recent application list for MIDI innovations:</div>
<div style="direction: ltr;"><a href="https://midi.org/innovation-award/psimidi" id="OWA6f353857-9d9b-cd9b-0f6c-73fb2404817a" class="OWAAutoLink" shash="qWaPm8jkjpQN1Ser2WwNQ9gBJ4z+0wCrJiA9mzSDU71u737XxQCFbh/q5D3hi4kSjI0itHi6h2JYUMi+ZCmpcRgbIdXr4qM1NUo/N11azLLZauw0bs0uWRFd2mCTZ41tgndTOGdIduQoEBhKroOjnzyes4gJchGbOhV3qRrlb/4=" originalsrc="https://midi.org/innovation-award/psimidi" data-auth="Verified">https://midi.org/innovation-award/psimidi</a></div>
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<div style="direction: ltr;">On Thu, Jun 27, 2024 at 7:54 AM Martin Klang via Synth-diy <<a href="mailto:synth-diy@synth-diy.org" id="OWAa2d461b3-11b4-acc6-5d41-8ea922974de8" class="OWAAutoLink">synth-diy@synth-diy.org</a>> wrote:</div>
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Well the input, if MIDI compliant, is protected by an optocoupler. Shouldn't that be enough?</p>
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I've seen plenty of DIY and not-so DIY circuits where the output comes straight off an MCU pin, which makes it susceptible to over-voltage and current. I'd put a transistor in line at least.</p>
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Martin</p>
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-----Original message-----<br>
<b>From:</b> Mattias Rickardsson <<a href="mailto:mr@analogue.org" id="OWA4846b0fc-ce9c-6dc3-92c4-6d9ede954e77" class="OWAAutoLink">mr@analogue.org</a>><br>
<b>Sent:</b> Thursday, June 27 2024, 4:29 pm<br>
<b>To:</b> grant <a href="http://musictechnologiesgroup.com/" id="OWAf3a28c91-57a1-95f7-e7f3-47f507c7d086" class="OWAAutoLink" shash="lGOaHgMyl9JLbrG1ekHx3TLDeuBhpcYrvl9Lhzh64LTC5+VPs6Q9uJzdUhcY8bzSBnhCi4ABAcgmsszYFTRzntySoIadYvcOaTjDssqBi5m64Sc+qug1rpKVGG0pwpLw207n6eHelakNNWW9e41AlAvgUHisuyWV3IPF2eaBAsI=" originalsrc="http://musictechnologiesgroup.com/" data-auth="Verified">
musictechnologiesgroup.com</a> <<a href="mailto:grant@musictechnologiesgroup.com" id="OWAeb0a03e3-21e7-e140-3013-e40d6f97f756" class="OWAAutoLink">grant@musictechnologiesgroup.com</a>><br>
<b>Cc:</b> <a href="mailto:synth-diy@synth-diy.org" id="OWA2c2951b7-45a4-e761-f875-a4d7e999793a" class="OWAAutoLink">
synth-diy@synth-diy.org</a> <<a href="mailto:synth-diy@synth-diy.org" id="OWA9f3695b6-9197-698f-7f89-92340ebb4cb3" class="OWAAutoLink">synth-diy@synth-diy.org</a>><br>
<b>Subject:</b> Re: [sdiy] MIDI cable impedance and MIDI In ESD protection?<br>
<div style="direction: ltr;"><<a href="mailto:grant@musictechnologiesgroup.com" id="OWAa5fb7daa-d0ee-0fb8-c3a6-62073f326445" class="OWAAutoLink" title="This external link opens in a new window">grant@musictechnologiesgroup.com</a>> wrote:</div>
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<div style="direction: ltr;">The latest MIDI electrical spec CA33 shows "optional ferrite beads to improve EMI/EMC performance (FBx 1K @100MHz)"as well as "optional small capacitor (0.1 μF typical) to improve RF grounding", along with diagrams.</div>
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<div style="direction: ltr;"> </div>
<div style="direction: ltr;">And I realize that the TRS MIDI spec (RP-054 from 2017-18) writes an unspecific answer to my other question:</div>
<div style="direction: ltr;"> </div>
<div style="direction: ltr;">"Because TRS connectors are often used for other (non-MIDI) purposes, manufacturers are strongly advised to add protection circuitry (e.g. to handle the case when a DC-coupled headphone driver is connected to a MIDI output)."</div>
<div style="direction: ltr;"> </div>
<div style="direction: ltr;">In the world of massive Eurorack systems and tiny plastic synths I expect that pretty loud signals are sometimes connected to MIDI Ins & Outs when confusing TRS MIDI with audio cables. But I wonder what the MMA would suggest that
this protection is made, not only in the output case that they mention as example. :-) </div>
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<div style="direction: ltr;">/mr</div>
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<div style="direction: ltr;">Andrei Kudryavtsev,</div>
<div style="direction: ltr;">Deftaudio <a href="http://www.deftaudio.com/" id="OWAd721c4d6-ea49-3cc8-e25b-c0850c5ca12b" class="OWAAutoLink" shash="HGGc+CbU2nXRBEG2BX2wrjr4EM0g1eD06OMqqX6Ya/OM1NmUYcqmY82v5G/aDH4pU16A07rE8vS2WPLDMLZTTC/xF0QxO7MyPKHy6nWnRHQ4VTpj6HlsKER4BeBtr3uju/iJzfGBb/clTqQ1jz1gnnDrSeygknAfvxQESG+7uxc=" originalsrc="http://www.deftaudio.com/" data-auth="Verified">
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<div style="direction: ltr;"><br>
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<div style="direction: ltr;">Follow me on <a href="https://www.facebook.com/andrei.kudryavtsev.5" id="OWA99a956ef-388c-6684-1246-6c0ac3f9f35a" class="OWAAutoLink" shash="xQbpylKd2euON3SXINFNxtshd1WSEL4F1IBqrRNYopF4PYYJjnGBBBsjX/Mt9/MUXg84ei888vcAPPw5Atgw9516P8fJJA9FATrg6ExGNGjjc6p46epOSvESGwYvugMXak2ChBV4uX3kY5jpQbZ6CCkFSo3aSKc0X0Uqm7puRKI=" originalsrc="https://www.facebook.com/andrei.kudryavtsev.5" data-auth="Verified">
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