[sdiy] MIDI phantom power...over 5 pin MIDI connector ?

[rsdio at audiobanshee.com]

By the way, the second caveat of this approach is that you will have a ground loop between input and output, making your MIDI device fail the usual MIDI guarantee that there won't be any ground loops.

You can solve this by filtering your pin 2 output so that it's connected to ground through a high impedance, but that means you cannot chain more than one MIDI phantom-powered device.

Brian


On Sep 11, 2015, at 12:50 PM, rsdio at audiobanshee.com wrote:
> Out of respect for your original question, I think the answer is:
> 
> Just hook up a charge pump to pins 2 & 4, using pin 2 as the ground.
> 
> The caveat is that this will not work in all cases. The good news is that I mentioned the MAX1595 part that will work even with 3.3 V MIDI Out designs. The bad news is that some devices will have a high impedance between pin 2 and signal ground, so your device won't work. The solution there is to design for external power, maybe with protection diodes to allow both options, so that you can power your device externally when it fails to steal power.
> 
> Brian
> 
> 
> On Sep 11, 2015, at 12:39 PM, Jean-Pierre Desrochers <jpdesroc at oricom.ca> wrote:
>> Hi again folks,
>> 
>> This DIY request is getting toooooo deeeep for me...
>> I was just asking for any easy solution to do it.
>> Thanks anyway guys!
>> 
>> JP
>> 
>> -------- Message original --------
>> Objet: Re: [sdiy] MIDI phantom power...over 5 pin MIDI connector ?
>> Date: 2015-09-10 07:20
>> De: jpdesroc <jpdesroc at oricom.ca>
>> À: synth-diy at dropmix.xs4all.nl
>> 
>> Hi all,
>> 
>> From my first DIY email request on that subject
>> I'm just trying to 'steal' power from a MIDI out connector
>> using only pins 2 & 4. I know this way I'd lose any GND references
>> but I'm still asking to get new ideas from great people like you guys !
>> You know, this device could have a floating GND reference.
>> Doesn't matter as far as my final MIDI powered device can cope
>> with it's incoming MIDI signal and send 'enough strong' MIDI info
>> on it's output.
>> 
>> JP