Phantom power MIDI troubles?

H

HenryWard

New Member
Hi folks,

I'm writing to ask for some help with the XLR6 Phantom Power setup for the Axe III, since I've been having some challenges getting it working. Fractal has already shipped me a second phantom power box and I bought a second cable but it's still off, so I'm thinking either (a) something more insidious is wrong like an issue with the GT22 itself, or (b) I'm just an idiot somehow, and I'd love to have your help debugging the latter possibility.

Context:
  • I can get bidirectional MIDI working successfully when using two five pin cables into the MMGT and powering the MMGT directly. Tuner works, patches/scenes change, etc. etc. This suggests to me that something is wrong in XLR6 connection.
  • If I unplug those same MIDI cables from the MMGT, and the same power, and plug them into the phantom power box, and then plug the phantom power box to the MMGT via the XLR6 cable, the MMGT powers on but has no MIDI communication either way. I've verified I'm not just plugging the MIDI cables in wrong, and they're never even leaving the Axe III.
  • Everything is on the very latest firmware, updated last night, but I was having the same problems before the last gen of Axe/MMGT firmware too.
  • MIDI channel is 1, Axe FX is set with program change ON and SysEx ON.
  • MMGT has Axe on Channel 1, bidirectional MIDI set to ON, MIDI Receive channel 1, everything else off. The Axe is set up to use MIDI Port "MIDI Out", Send PCs is ON, Ignore Incoming PC/CC are on (because I'd rather the MMGT *not* follow AXE-Edit or the like), Send CCs on Preset Change and Poll State are ON.
  • This is possible paranoia, but the male 6-pin connector on the MMGT itself is a little "loose" - not much, but the pins do wiggle a teeny bit when I touch them, if that's relevant at all.
Is there anything obviously wrong here or anything else I should do to test? Everyone at RJM has been awesome with the help, shipping the replacement Phantom Power box for free and etc., and I'd hate to ask them about shipping the GT itself back for diagnosis now unless it's verifiable that I'm not just missing something obvious that should be making this work. Thanks all!
 
Can you try another XLR6 cable?

You've already concluded the MIDI cables are fine. And you know the GT/22 is getting power via the phantom power box over XLR6 because it powers up, right?
 
If the two cable connection works fine, then we know that those two MIDI cables are good. The Bidirectional MIDI setting is the only setting that would prevent the single cable connection from working, and you've already addressed that.

Double check the connections to the phantom power box - note that the connections are labeled "To MIDI Input" and "To MIDI Output" - most devices have a MIDI input that connects to a MIDI Output on the other side. With the phantom power box, "To MIDI Input" needs to connect to the MIDI Input on the other side. Just wanted to mention that, that's caused problems for others.

If all that checks out, it has to be the cable, the phantom power box or the GT itself. We did have a bad batch of phantom power boxes not too long ago, but if we sent you a second one, we would have tested it for sure. We definitely went through them all once we discovered the problem. Since you're fairly nearby, it might be best to send the boxes and cable to us so we can sort it all out. If you email us at the support email address, we can set up an RMA.
 
I have the same problem as @HenryWard.

* Axe Fx III and MMGT 22
* without phantom power everything works OK
* new phantom box from RJM, 2 midi connectors + xlr6
* new original xlr6 cables from RJM (3-meter, 9-meter)
* quality 5pin midi cables
* running only power, no midi response
* all completely checked, all cables changed twice, all properly connected .... definitely

I do not know what else :-((
 
As far as i know
got this from someone in the axe forum


The schematic is very simple:


For the RJM, it doesn't matter what is + and - for the power supply.

The Midi-cables use pin 4 for the + and pin 5 for the -

So:

3 from the GT goes to the 4 of the Midi OUT of the AxeFx

4 from the GT goes to the 5 of the Midi OUT of the AxeFx

5 from the GT goes to the 4 of the Midi IN of the AxeFx

6 from the GT goes to the 5 of the Midi IN of the AxeFx
 

Attachments

  • Midi xlr gt22.jpg
    Midi xlr gt22.jpg
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Thanks, buddy

I do not assume that the problem is in connecting the connectors. I ordered the cables directly from RJM. They came original for this phantom box. Rather, I'm afraid the bug is in the power box or in GT 22 ...
 
Yes, of course the bidirectional midi is ON.
When I was already desperate, I created a complete basic configuration for AxFix III through the hardware buttons in the GT22. To avoid errors in my preferred configuration. Midi control through the phantom box does not work, but the power is functional. Then I did the classic plug-in of 2 midi cables and a power adapter. Everything worked.
So ... my conclusion is that in a normal connection without a phantom box everything is working correctly. After connecting a phantom box, midi communication does not work.
I'm sure the problem can only be in the phantom box, or in the GT22 xlr6 connector ... I've phased out all the other options.
 
If you're willing to have a look at the inside of the phantom power box, I can send you a diagram of how it's supposed to be wired. That would be the easiest thing to check. It's also the easiest thing to fix, if you are handy with a soldering iron. We did have a bad batch of phantom power boxes that were wired incorrectly. Some did get shipped out before we realized there was a problem.
 
Thank you, I think it's a good idea. I can try to fix it according to the diagram. If it's easy for my old fingers :)
Please, send me a diagram of the connection.
 
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Sorry for the delay, here it is... Also, sorry to put you to work like this, but this is definitely the fastest way to fix the problem.
 

Attachments

  • PPA-XLR6F-2.pdf
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You are very kind and friendly. Thank you for your willingness. Tomorrow I will try to solve the problem. I'll give you the info :)
 
The scheme confirmed that both midi connectors in phantom box were incorrectly connected. They had cables replaced by each other. After a half-hour of simple work, everything works correctly.
Friends of RJM, thanks to willingness and effort to solve my problems quickly :)
Cheers
 
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