Bi-directional MIDI with phantom power over one cable?

unix-guy said:
I think you're not understanding the spec you posted. You'll notice in every diagram that only 3 pins are wired. Pins 1 and 3 are N.C. (not connected). The other 3 pins are RX, TX and GND.

The signal voltage is used for the actual midi transmission as far as I remember.
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I guess I was misunderstood in my posts. Yes, 3 conductors are the standard.

Bi-directional MIDI, has used the other 2 conductors available on the DIN connector...at least as long as I can recollect. And yes, Axe-3 does not afford that.
 
I'm a bit confused with what @squealie is saying...

This was the pinout on the 7-pin MIDI Input of the Axe-Fx 2 (previous model):

1645032820253.png

1 - MIDI Out+
2 - No Connection or Ground
3 - MIDI Out-
4 - MIDI In+
5 - MIDI In-
6 - Phantom Power
7 - Phantom Power

Unlike the Axe-Fx 2, the Axe-Fx 3 [1] does not support bi-directional MIDI over just one of its 5-pin MIDI jacks, and [2] cannot phantom power a controller (it has no 7-pin MIDI jack or phantom power jack).

With the Axe-Fx 3, for bi-directional MIDI, you must either...

[1] Run two 5-pin MIDI cables between the Axe-Fx 3 and your MIDI controller (one from the controller MIDI Out to the Axe-Fx 3 MIDI In, then one from the Axe-Fx 3 MIDI Out to the controller MIDI In).

or...

[2] Run one 5-pin MIDI cable connected to the combo MIDI In/Out jack on your MIDI controller to an adapter (or breakout box) that splits this cable into two discrete 5-pin cables (MIDI In and Out) for the Axe-Fx 3.

As for phantom power to your controller...

A unit like the Mastermind GT accepts power over pins 6 and 7 of its 7-pin MIDI Out jack, but an adapter (or breakout box) is again required to slip the power from the Mastermind GT power brick in on those pins (even the phantom power jack on the Axe-Fx 2, rated for a max current of 1-amp, couldn't safely handle the 3-amp power brick for the Mastermind GT).

Both the Voes M-Box and RJM PPA-DIN7F-2 adapters (aka breakout boxes) will solve both issues:

[1] Bi-directional MIDI data split/combo (between a MIDI controller able to send/receive data over one MIDI jack and the Axe-Fx 3 requiring data be received and sent on two discrete MIDI jacks).

[2] Supply power on pins 6 and 7 to a MIDI controller that accepts phantom power over these pins (via a 7-pin MIDI cable of course).
 
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7 pin Din (MIDI) is a common workaround.

The Voes box you are looking at solves your issue.

I'm arguing, that the original MIDI spec leaves 2 conductors unused in a DIN(5) and that 5 volts is supplied from the input side. Not all devices complied.
 
squealie said:
I'm arguing, that the original MIDI spec leaves 2 conductors unused in a DIN(5) and that 5 volts is supplied from the input side. Not all devices complied.
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The mastermind requires 12 volts. Their breakout box is for use with an external power supply since the 5 supplied by midi spec is insufficient for that controller.
 
The M-box will work with any device that support 7-pin power.

It is a passive box , 7-pin Midi is split in:

Clipboard01.jpg

pin 1 & 3 Midi In
pin 2 Ground
pin 4 & 5 Midi Out
pin 6 & 7 Power

By my knowledge beside the Voes MC and MX devices, RJM, Liquid Foot and the Axe-Fx II support this.
Even if the Midi In is not used, the M-Box can be used to transfer Midi Out and Power. Several Midi Devices support this.

More info on www.voes.be

M-Box schuin Midi.jpg


M-Box schuin Midi-7.jpg
 
squealie said:
I guess I was misunderstood in my posts. Yes, 3 conductors are the standard.

Bi-directional MIDI, has used the other 2 conductors available on the DIN connector...at least as long as I can recollect. And yes, Axe-3 does not afford that.
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I was replying to your comment on use of phantom power being in the original midi spec. It isn't...

Additionally, yes, people have used the unused pins for other purposes... But as I said before, that is not in the spec and it's inconsistent.

For example, Voodoo Labs uses those extra pins for power. Plug one of their devices that provides phantom into another device that expects to use them for bidirectional comms and you will have a problem. There's a warning in the VL manuals about that.

squealie said:
And you'll notice that 5v is on the input.

That you missed.
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Actually, I didn't. I said "signal voltage". That is what I was referring to, and it's for the Midi itself, not for powering other devices.
 
NattyBar said:
Yup - also the box that I’m using for the Mastermind LT. Its taped to the side of my rack case - always plugged into the the Axe III and a power adapter.

All I need to do for set up is plug the MIDI cable from the breakout box to the LT and I’m set.
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I have a Vafam patch panel on the front of my rack, and the 7-pin output of the box runs there. Very easy for hooking up on a dark stage, and keeps all of the internal patch cords short and direct. One BTPA 7 pin cable to stage front for the MMGT/22 and I'm good to go!

Ron at RJM is great to work with, and has been very responsive to the needs of Axe FX users. I seriously thought of changing to the FC12 when it came out, but once you're used to the displays on the RJM, and all the things it can control, it's hard to walk away.
 
Rick said:
I have a Vafam patch panel on the front of my rack, and the 7-pin output of the box runs there. Very easy for hooking up on a dark stage, and keeps all of the internal patch cords short and direct. One BTPA 7 pin cable to stage front for the MMGT/22 and I'm good to go!

Ron at RJM is great to work with, and has been very responsive to the needs of Axe FX users. I seriously thought of changing to the FC12 when it came out, but once you're used to the displays on the RJM, and all the things it can control, it's hard to walk away.
Click to expand...

Ron is world class! Been extremely helpful even for us international customers. I’ve owned the MM and PBC controllers - customisation is amazing and comes with exceptional service.
 
I own a couple of RJM boxes and have built my own.

One thing to note is the 7 pin cable needs heavier conductors to power the RJM than most typical 7 pin midi cables.

If you need any info let me know. My custom made one mounted direct to a 1U strip
 
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