Midi out powered ?

[manki]

My question is concerning the midi output jack.

I currently use an Alesis Trigger IO, and for some stage performances i need to have the drum samples triggered remotely (which are on an MPC Live II).

I've been using a CME WIDI bluetooth midi dongle to relay the midi information without cables, it's rock solid, but can only be powered through the midi out port of a device, the vast majority of midi gear can supply this power but not all devices give out the necessary voltage out of their midi ports, for instance i have an old roland midi keyboard from the 90s that doesn't work with the WIDI.

Also plan on powering the eDRUMin with a USB power bank like i'm doing with the Alesis, so my question is :
would the WIDI get power from the eDRUMin's midi out port while it being powered by a USB power bank ?

Thanks for your time,
Francis.

[Rob]

The eDRUMin output follows the MIDI spec in this regard. Its 3.3v, but I'm not entirely sure the max current it provides.

UPDATE: The MIDI out power has a 47 ohm series resistor, so you should easily get 50 ma.

[manki]

thank you Rob for such a quick response, i have another question, but it's on a different subject so i'll start a new thread in case someone needs to find that answer in the future.

[djbclark]

The eDRUMin output follows the MIDI spec in this regard. Its 3.3v, but I'm not entirely sure the max current it provides.

UPDATE: The MIDI out power has a 47 ohm series resistor, so you should easily get 50 ma.

Can it be powered via USB while data still going out the 5-pin DIN MIDI out? I'm thinking WIDI on the 5-pin plus an external cell phone battery on the USB is the way to go. But if needed could also hook up a 9v battery to the 9v in.

[djbclark]

I've been using a CME WIDI bluetooth midi dongle to relay the midi information without cables, it's rock solid

Have you noticed any latency issues using the WIDI with the eDrumin?

[djbclark]

The eDRUMin output follows the MIDI spec in this regard.

If you ever want to add Bluetooth as a feature, this looks interesting: https://www.cme-pro.com/widi-core/

As far as I can tell CME owns the market on low latency MIDI over Bluetooth.

[djbclark]

Can it be powered via USB while data still going out the 5-pin DIN MIDI out? I'm thinking WIDI on the 5-pin plus an external cell phone battery on the USB is the way to go. But if needed could also hook up a 9v battery to the 9v in.

The answer to this is it doesn't work for me at all getting only power via USB with MIDI going through the 5-pin DIN port. Using a 9v battery I can only get it to work once before the eDrumin4 seems to have destroyed it. No idea where the fault lies, but I'd suggest trying hardware other than the CME WIDI Master with the eDrumin4 (note I tried 2 different units with 2 different levels of firmware.)

[djbclark]

Also with the 2nd unit I tested the CME WIDI Master with some other hardware first, worked fine, then did not work after being attached to the eDrumin. So would suggest you only try other hardware within the free return period.

I had a doreMIDI around a so tested that, it works fine. Unlike the CME it gets power via USB, so I'll have to get a Y splitter cable to run off my battery pack, but that's just $7. Also not as pretty but oh well.

I have a "Xvive MD1" on order, it also gets power from 5 pin din, I'll report back on that soon, should help bisect to what's at fault.

Update: on Amazon people are saying this device is a clone of the WIDI Master, to the point it takes the same firmware updates. So will try but results won't be too useful to bisect. If you know of any power over MIDI Bluetooth devices that are not clones of the WIDI Master, please let me know.

[djbclark]

As expected, the Xvive MD1 testing went exactly the same as the WIDI Master. Using the "MIDI Connect" app on Android. First tested some other hardware, a keyboard and a tabletop drum set, went fine. Initially eDrumin also went fine, however after disconnecting and reconnecting would not work. Went back to other hardware, the MD1 now also did not work on that hardware. Lots of Android reboots etc. to make sure that wasn't the issue. Also tested the doreMIDI in same way, it was fine.

Differences this time: worked with eDrummin on USB power. Last time I used a USB battery pack for eDrummin power, this time was connected to high quality USB hub.

Let me know if there is something else out there that isn't just the WIDI Master with different firmware and branding.

I know about the Yamaha and Roland devices, but they require power from both in and out MIDI ports, and also the dangling MIDI out would be annoying. WIDI Jack is the only other thing I can think of to test at the moment, but not sure it'd be much better than the doreMIDI + cable ties.

[Rob]

When powered via an external power supply, the ED4 needs to drop the input voltage down to 5V, and that produces heat. The onboard 5v regulator will go into shutdown mode if it gets too hot, and that can easily happen if your input voltage is too high and you are drawing lots of current, which I suspect the WIDI Master is doing.

The ED4 (which uses a L78L05ABUTR) on the external power connector should be stable with about 7V. If you have a power supply that goes down to around 7V, that would probably do the trick.

Alternatively, don't use the external DC power connector. Instead power the ED4 with a USB charger.