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PHANTOM POWERING THE GT

Discussion in 'GT General Discussion' started by rjmmusic, Feb 28, 2013.

  1. rjmmusic

    rjmmusic
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    The Mastermind GT draws a lot of current due to its many LCD displays. The backlights of these displays draw varying amount of currents based on the colors being shown. The maximum (with all displays turned white) is around 1600mA. This is a lot more than a typical MIDI controller, so you have to take care to make sure your device can handle that load when phantom powering the GT.

    Products that are able to phantom power the GT
    At this time, only our own devices have been successfully tested to phantom power the GT:
    • Amp Gizmo
    • Effect Gizmo (both the original model and the new one with the 6-pin XLR on the front panel)
    • Mini Amp Gizmo
    • Mini Effect Gizmo
    • Rack Gizmo
    • RG-16

    Important Note: when phantom powering with our devices, use the GT's power supply to power the device! The supplies that ship with all of our other devices are not able to provide enough current for the GT.

    Products that known NOT to be able to phantom power the GT
    • Axe-Fx II - it will be damaged if you try!

    We recommend not using any other device to phantom power the GT unless the manufacturer can confirm that the device can safely supply 12 volts at 2000mA from its phantom power jack. We will be testing other devices and adding them to this list when possible.

    What to do if my device can't phantom power the GT?
    The simplest thing to do is to power the GT directly with its own adapter. Just make sure that you never connect it to a power adapter AND a phantom power source at the same time! When it doubt, use a 5-pin MIDI cable to connect to the GT. 5-pin cables will work fine, but will not pass phantom power.

    We also make a phantom power adapter box. This box has a 5-pin DIN input and a DC power input, which are combined to provide a phantom powered MIDI connection over a 7-pin DIN or 6-pin XLR connector. You can mount this in your rack and use it as the connection point for your GT's MIDI cable. The box will pass bidirectional MIDI, making it ideal for use with an Axe-Fx - or pretty much any MIDI device.

    What's the difference between the 7-pin DIN connection and the 6-pin XLR?
    There's very little difference. They both can carry bidirectional MIDI communication and phantom power. The XLR connectors are more sturdy and will lock into place. 7-pin DIN's advantages over the 6-pin XLR are that they're more standard - many products use them - and they're also a little less expensive. We make a variety of 7-pin DIN to 6-pin XLR adapter cables to adapt from our equipment to others'.

    A note on 7-pin MIDI cables
    Off the shelf MIDI cables (the ones with black plastic connector housings) use very thin wire, which can be a problem with high current draw. We have not seen a specific problem yet, but such cables will definitely cause the GT to draw more current than it normally would, and this could be a problem in the long term. We don't recommend using them, just to be safe.

    Using hand made cables with larger gauge wire is recommended. Our cables use 24ga wire internally, which is a larger diameter than any other 7-pin MIDI cable I've seen. We can't go any larger and have it still fit through the back of the connector!
     
  2. kenora

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    Will the VOODOO LAB GCX phantom power the MASTERMIND GT?
    Using a 7 pin midi cable (pedalsnake)?

    Thanks
     
  3. rjmmusic

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    I suspect that it won't. What does the GCX's power supply say on it? (It should say something like 9VAC 1000mA)
     
  4. kenora

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  5. Gibertoni

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    Question from someone who does not understand anything at all electronics.

    A custom Midi cable mounted as in the example below can be used to phantom power the Mastermind GT?

    Midi cable with 7-pin attached in Midi Out of MMGT, with the pins 1 to 5 connected to the Axe-Fx, and pins 6 and 7 to Rack Gizmo for Phantam power.
     

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  6. rjmmusic

    rjmmusic
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    Yes, that would work, if a little tricky to make.
     
  7. AlexMania

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    Hi Ron,

    I'm happily phanom powering my GT16 from a mini FX Gizmo (yes, I used the GT's power supply into the Gizmo). I also power my Wah and tuner from the GT, so in total, I'm powering my GT16, Wah, and Tuner from a single 7 pin midi cable.

    Getting a true 7 pin cable that isn't wafer thin isn't so easy. Can you make me a nice and fat ten foot 7 pin MIDI cable?

    Alex
     
  8. Mr.E

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    Are Ethercon cables safe to use?
    I like to use Ethercons because you can use any RJ45 patch cable as a backup.
    But I'm concerned the wire is too thin for the 1.6 amps the GT draws.
    Would this be a good alternative:
    http://www.thomann.de/nl/major_steuerleitung_8x014mm.htm

    The XLR on the GT seems like a good alternative.
    What kind of cable would you recommend?
     
  9. rjmmusic

    rjmmusic
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    I wouldn't recommend CAT5/CAT6 cable - I haven't tested it, but the wire is pretty small which makes me concerned.

    For making long DIN-7 or XLR-6 cable, we use either Carol Cable C0744A or Belden 9538. Best-Tronics also makes a very good 8-conductor cable, although it's hard to get DIN connectors on the cable - the cable is just a little too large. You can do it with some persistence and some kind of lubricant. Mogami also makes an 8-conductor cable but I don't prefer it because the conductors are smaller than the others.

    The cable you list uses smaller conductors than the cables we use - the specs claim that the conductors are 0.14mm^2 - ours are 0.2mm^2, a pretty significant difference.

    For long cables (starting at 30 feet / 10m) we always use 8-conductor because we use two wires for each phantom power pin. That cuts the resistance of each connection by half and doubles the amount of current it can carry on those pins.
     
  10. Mr.E

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    Thanks for the info Ron.
    For those who are looking for those cables in Europe:
    Belden can be bought here :
    http://be.farnell.com/jsp/displayPr...d|38390108667|kword|belden 9538|match|p|plid|

    I've been looking at some other alternatives:
    I've seen mixed cables with thin wires for data and thick wires for current.
    http://www.thomann.de/be/sommer_cable_monolith_2_dmx_combi_cable.htm

    Or a Cat7 0.26mm²
    http://www.thomann.de/be/sommer_cable_mercator_cat7_pur_xl.htm

    Or a Cat5 of 0.15mm² and use 2 x 2 wires for power as you suggested
    http://www.thomann.de/be/sommer_cable_mercator_cat5_pur.htm
     
  11. kurtr2

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    Hi Ron,

    I bought your DIN7F to phantom power the GT and get bidirectional communication with the Kemper. question: how do i power the DIN7F?

    thanks,
    Kurt
     
  12. rjmmusic

    rjmmusic
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    Use the GT's power supply to connect to the box, and everything will work correctly.
     
  13. Alexander

    Alexander
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    Hi Ron,

    I want a backup power supply.
    Can I buy just any power supply that has the correct ratings?
    Or are there special requirements/specifications?

    Thanks
     
  14. rjmmusic

    rjmmusic
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    You can use anything that provides 9 to 12 volts with enough current for your particular model of GT.
     
  15. Alexander

    Alexander
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  16. jjozwia

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    Awesome, this thread was what I needed too. Cheers
     
  17. Johan Allard

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    I’ve recently been thinking of simplifying my live setup and get back to using my Axe Fx in a 2RU rack and that will make fitting the adapter box a little bit tricky. I’ve thinking of the possibility of using a 5-7 pin midi cable instead (which effectively has the adapter box builtin to the cable: http://btpa.com/5-to7-Pin-Midi/. Will these work with the Axe Fx and MMGT?
     
  18. rjmmusic

    rjmmusic
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    It depends on the length of cable you will be using and the model of GT you have. If you need a long cable (8m or longer) and you have a GT22, it might not be able to handle the current draw. In that case, I'd ask Best-tronics to use two wires for each power connection. If you talk to Brad at Best-tronics, he'll know what i'm talking about and would be able to get the right cable built.
     
  19. Mr.E

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    For the European customers:
    I found a cable for 2way MIDI & Power:
    http://www.thomann.de/be/sommer_cable_sc_octave_tube.htm
    [​IMG]

    Sommer Cable SC-Octave Tube, Dia PVC 6,5 mm, Internal cores (Audio) 5 x 0,14 mm2, (Control) 2 x 0,50mm2, thomann copper spiral shielding, weight per meter 67g, colour grey

    Neutrik NC6 FDL1 B
    [​IMG]

    Neutrik NC6 MX-B
    [​IMG]
     
  20. Alexander

    Alexander
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    So when using this cable, I don't have to use the phantom power box?
     

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