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One thing that this article mentions is that MIDI is a interface that is inherently optically coupled. The notionally differential wires end up in the LED insid
by dfox 3y ago
One thing that this article mentions is that MIDI is a interface that is inherently optically coupled. The notionally differential wires end up in the LED inside of an optocoupler. Reason for that design is a general aversion of audio people to anything that might cause what they call “ground loop”.
And then well, in 21st century there are various half-assed implementations of the MIDI physical layer (mostly assuming that it is essentially a TTL) that end up non-working and non-working because of the ridiculous currents that flow through the cable that shorts ground of one device to the power bus of another.
- pantulis 3y agoI swear I have _heard_ sysex dumps on my speakers, specially using older serial "To-Host" cables.
- boffinAudio 3y agoYou have to try pretty hard to mess up MIDI, hardware-interface wise. Its one of the most widely understood and implemented serial protocols out there ..
- jalk 3y agoHere is a snip from the midi specification > The MIDI circuit is a 5mA current loop; logical 0 is current ON.... To avoid ground loops, and subsequent data errors, the transmitter circuitry and receiver circuitry are internally separated by an opto-isolator Ground loops is not something the audiophools have cooked up. Ethernet devices are also isolated from each other, although it uses 1:1 transformers (Ethernet Magnetics) instead of optocouplers. The optocoupler also works like a cheap (although somewhat hard to replace) fuse which is probably a good thing if you want to connect you Roland Jupiter-8 / Fairlight CMI to some dodgy equipment.
- zdw 3y ago> Ethernet devices are also isolated from each other, although it uses 1:1 transformers (Ethernet Magnetics) instead of optocouplers. Unless you're using fiber as your medium, but that's an optocoupler by definition...
- grawlinson 3y ago> The optocoupler also works like a cheap (although somewhat hard to replace) fuse which is probably a good thing if you want to connect you Roland Jupiter-8 / Fairlight CMI to some dodgy equipment. In this case, the older synths are more likely to have failing/dodgy components. I have a DX-7 that I'm going to have to replace a lot of components in, and this sort of knowledge/understanding really should be more common along synth enthusiasts.
- datpiff 3y ago> Roland Jupiter-8 / Fairlight CMI Funnily enough neither supported MIDI. The CMI Series IIx got it as an upgrade, the Jupiter-8 only supports it with 3rd party modifications.