I wasn't clear what I meant by "the devices" in "powering the
devices" (from a 5V source, maybe on the synth's MIDI DIN). I'm talking
about deriving 5V supply from the synth's MIDI DIN to power the MIDI
USB to DIN Converter device (from whichever maker). So the Converter
would be at the end of a long MIDI cable carrying 5V power from the
synth to the Converter, then a maybe 2m long USB cable from the
Converter to the controller.
If the synth's 5-pin MIDI DIN provides 5V I can use at the
Converter, by a breakout adapter at the Converter providing 5V to the
Converter's separate 5V power input socket, that's great. Or if that 5V
isn't usable that way, maybe the answer is a 5-pin to 7-pin adapter at
the synth, with separate 5V power supply injected into the extra 7
pins. Then at the 7-pin cable end at the Converter, a breakout that
extracts the extra 5V power supply connected into the Converter's
separate 5V power input.
Maybe use an output from my CV module at the synth end as the
5VDC power supply, rather than use an extra wall wart. It's a Moog
Mother-32 - does that have a CV out providing 5V that can power the
Converter?
Post by ***@yahoo.com [KurzList]I am not following your logic here.
Technically, I suspect both the controller and synth will be
consuming "end-points" (in principle) drawing 5V rather than
supplying it, unless the synth designates a "host USB port". In this
case, a powered USB hub will be required between the deivces, in turn
powered from the wall. The power will never be at the controller end
of the cable in this scenario.
Secondly, in the absence of a "host PC", or a host port on the
keyboard, why will the devices talk to one another? USB is not just
about cables and power, there is the data routing to consider, and
that requires intelligent parsing of data.
Thirdly, and assuming you solve the "host" issue, a long USB cable
has physical limits and maximum cable length, beyond which you will
experience dropouts. USB works best over shorter runs, especially
when expecting high frequency data rates.
Fo uthly, "Power over MIDI" is not widely implemented. In the past
it provides guitar footpedals with a 9V DC feed, so saving on
cabling; sometimes the ports have 7 pin DIN sockets; it can also mean
very lower power devices are able to steal some voltage from the MIDI
signal itself, provided that the ground is connected, which it often
is not. Yes, technically, you could create a supply on your 19inch
rack using a custom wired patch panel which adds a 5V DC level - but
will the MIDI IN socket the other end support it without a mod? The
mod would replace the MIDI IN 5 pin DIN socket with a 7 pin DIN
socket and jumper the incoming power to the 5V rail. You would NOT
typically run 5V from the IN on the patch bay to the OUT on the
controller, which is implied by your desired plan.
It is however not particularly complex to create a custom loom with
separate MIDI, USB, and 5V DC feeds, either on a single multicore
cable, or several cables in a braid, with tidy heat shrunk ends. Our
guitarist's live rig features this kind of cabling for expedient
setup times.
Peace.