Power requirements for GCP (phantom power)

Q & A for building and interfacing your rack gear with Ground Control Pro and GCX-based systems.
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drewzee87t
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Joined: Fri Jan 13, 2017 8:22 pm

Power requirements for GCP (phantom power)

Post by drewzee87t » Fri Jan 13, 2017 8:38 pm

Hi,

Using GCP with a Hughes & Kettner Grandmeister using its phantom power and 7 pin cable. The GCP works for a few minutes and then the lights get dim, thing starts schizzing out, and then I start getting crazy control messages being sent.

Unfortunately the solution seems to be plug in the GCP to a wall wart. On it's own power it works fine with no glitches.

H&K Manual lists phantom as 20VDC at 150mA on its midi in port. Just curious what the spec requirement is to power this GCP on phantom.

Anyone know someone that makes a box that you can plug a wall wart into back at the rack and have it apply power to the correct midi pins?

Curious if you have seen this before with the HK amps.

Thank you

bettsaj
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Location: Darkest Suffolk UK
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Re: Power requirements for GCP (phantom power)

Post by bettsaj » Mon Jan 16, 2017 5:37 am

The GCP requires 9vdc or 9vac, not 20vdc. That's why it works with the AC adaptor, and not your phantom power.

You'll need to run it from the 5 pin midi connector, and use some sort of routing box that the ac power adaptor can plug into to provide power to the 2 unused pins of the midi cable.

Please see this previous post..... I still have the routing box if interested ;-)

http://www.voodoolab.com/forum/viewtopic.php?f=9&t=7205
"My technique is laughable at times. I have developed a style of my own, I suppose, which creeps around. I'll never be a very fast guitar player."

David Gilmour

blewmeaway
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Joined: Wed Feb 16, 2011 6:08 pm

Re: Power requirements for GCP (phantom power)

Post by blewmeaway » Tue Mar 13, 2018 4:09 pm

Just wanted to confirm....the Grandmeister cannot power the GCP??? Is that true???

JohnClark
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Location: The Lab

Re: Power requirements for GCP (phantom power)

Post by JohnClark » Tue Mar 13, 2018 4:23 pm

Confirmed! 20V @ 150mA will not work to power a Ground Control Pro.

A Ground Control Pro requires 9V AC (or DC) and should really get at least 400mA.

I hope that helps!

blewmeaway
Posts: 20
Joined: Wed Feb 16, 2011 6:08 pm

Re: Power requirements for GCP (phantom power)

Post by blewmeaway » Tue Mar 13, 2018 5:29 pm

That’s a bummer but yes it helps a lot, thank you!

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