Re: [LAU] Galvanic isolation (was: Re: pianos with built in recorders?)

On Thu, 24 Dec 2015 03:58:31 +0100, Ralf Mardorf wrote:
>On Wed, 23 Dec 2015 17:42:29 -0600, Jonathan E. Brickman wrote:
>>> USB MIDI has got the risk to cause noticeable MIDI jitter.
>>>
>>> Does USB MIDI provide galvanic isolation? Several times I read
>>> claims that USB MIDI connections aren't galvanically isolated.
>>>
>>> Standard MIDI connectors make usage of opto-couplers and shield of
>>> the MIDI DIN connectors is open.
>>Certainly all of the USB MIDI connections I have ever tested, are not
>>galvanically isolated; I always get trouble with USB signals bleeding
>>over where they don't belong. USB-to-DIN adapters I have used have
>>been better, but not perfect. Is there a make/model of USB-to-DIN (or
>>even PCI-to-DIN if it exists anymore) which you know for sure has
>>opto-coupling? That would be a great boon to me. Sooner or later I'm
>>going to do optocoupling for audio too, probably using a TOSLink
>>setup.
>
>You can solder yourself or buy cables for serial port, resp. PCI
>sound card output with such a connector, that have build in
>opto-couplers. I remember this very good, because years back, when I
>started needing reading glasses, but didn't own them, I tried to
>resolder a a self made parallel port cable. I tried to add
                        ^^^^^^^^ serial (I'm sure I corrected the "typo"
                        before sending :S)
>opto-couplers and due to the missing reading glasses, resp. a missing
>magnifier, I damaged the jack. The cable worked without opto-couplers
>for my serial port, but didn't work for my Envy24 sound cards. I then
>ordered a cable for around 10,- € with build in opto-couplers.
>I own USB port to MIDI DIN, but never measured if shield is open and
>can't take a look inside, but I didn't experience electric noise caused
>by the USB to MIDI DIN cable, just jitter. My RME PCIe card has got
>break through MIDI DIN. I don't know if inside the connector or on the
>board are opto-couplers, but there are no noise issues caused by MIDI
>connections and there are no level issues.
>
>Discounter keyboards don't provide MIDI DIN connectors anymore, they
>provide USB MIDI onl

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