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Run GK3 on phantom power?
nix808
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PostPosted: Tue Jul 24, 2012 11:01 pm reply with quote
This prolly doesn't work,
and fry the GK3 hex pickup,
but can I run it on phantom power from my soundcard?
I have 48v phantom power switches.
The GK runs on 18v DC.
Is this gonna work?
It occured to me, so I thought I'd ask.
Cheers
I am burning 9v batteries at a rate of knots.
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Smoke the pipe of peas, human beans!
http://soundcloud.com/nix808
http://rekkerd.org/nix-plugs/
Phonics Audio
^ Joined: 21 Jul 2006  Member: #113899  Location: Melbourne, Australia
ew
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PostPosted: Wed Jul 25, 2012 8:26 am reply with quote
?

The GK3 doesn't use batteries. All power necessary is provided via the 13 pin cable...

ew
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justin3am
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PostPosted: Wed Jul 25, 2012 8:29 am reply with quote
It could cause a problem if GK thing is drawing more current than your sound card can provide. I think most microphones draw less than 10mA, so if your pickup/preamp draws more than that it could damage your soundcard.

If the GK connector has two unused pins, it may still be possible to run power through the cable but it may introduce interference. If you have 18vDC power adapter, you could cut off the barrel connector and solder the two leads to the unused pins (inside whatever you are using to receive signal from the GK pickup). Then you could wire those two pins on your guitar to the battery connector (use another battery connector rather than soldering wires directly to the connector so that you can use battery power if you need to).

I've done something like this with a MIDI cable and my FCB-1010 but a MIDI cable doesn't carry audio signals, so I'm not too worried about interference.
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tapper mike
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PostPosted: Wed Jul 25, 2012 9:53 am reply with quote
The power supplied to the gk is only for the light,

If you think you could bypass the processor such as the gr55, VG, or GI to attain a midi singla your efforts would be in vain. Basically you have 7 analog audio signals just like a guitar output one for each of the hex pickups and one for the conventional pickups. They send pitch which has to be converted to voltage and then in turn have to be converted to midi. This is why "The Box" (all gr series) have lower latency and better note accuracy then the midi out from the box. Internally GR's don't use midi for note tracking. It's when the signal is processed again from voltage to midi that most of the glitchiness occurs.

If you are thinking of running the hex pickup for an audio source from the guitar you would still need a merge box to convert it to a single mono line.

If you are thinking of using it as a direct 6 out ala gibson "dusk" you'd need a separate outbox as a pre. RMC used to make one and another company makes one now. The preamp before voltage to midi actually does make a lot of sense. You'll get greater stability and better sustain. However you'll always be toying with noise reduction and other issues to defeat ghost signals (something GK's are notorious for)

If you are looking for a cheap gateway solution from guitar audio to your soundcard pick up a direct box. If you are picking up noise it's prolly feedback from your computer and/or especially your screen monitor(especially crts)
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nix808
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PostPosted: Wed Jul 25, 2012 2:14 pm reply with quote
I am using the GK3 as a hex pickup.
It goes via the 13 pin into a breakout box which has battery connectors.
From there the 6 audio signals go into my soundcard, which has the phantom power.
I am doing my own audio to synth conversions.

What amps should I use for a power supplly Justin?
Thanks for the info on how much mics draw.

The 18 volts does more than power the light.
It boosts the signal by about 15 db.
Possibly I could use pres with more gain,
but I'm finding it tracks best when there is plenty of power.

Cheers
----
Smoke the pipe of peas, human beans!
http://soundcloud.com/nix808
http://rekkerd.org/nix-plugs/
Phonics Audio
^ Joined: 21 Jul 2006  Member: #113899  Location: Melbourne, Australia
justin3am
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PostPosted: Wed Jul 25, 2012 3:47 pm reply with quote
nix808 wrote:
What amps should I use for a power supplly Justin?
Thanks for the info on how much mics draw.


If you do a search for "18v power supply" you will get lots of results, anywhere from 300mA to 4+ Amps. I don't know how much your GK3 setup draws so I couldn't say what you will need. Generally it's safer to use a PSU that provides more current than you need, than less.
^ Joined: 07 May 2006  Member: #106746  Location: Southern California
nix808
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PostPosted: Wed Jul 25, 2012 6:54 pm reply with quote
Thanks Justin 8D
I guess if I do it, I will get a 2 amp one.
That should be enough.
----
Smoke the pipe of peas, human beans!
http://soundcloud.com/nix808
http://rekkerd.org/nix-plugs/
Phonics Audio
^ Joined: 21 Jul 2006  Member: #113899  Location: Melbourne, Australia
selfconstruct
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PostPosted: Sun Jul 29, 2012 8:07 am reply with quote
Careful how you wire that in. The GK-3 takes +7 and -7 volts (on the black and purple wires respectively, I think). So I'd guess your two 9v batteries are providing these two separate supplies. I'll have to do some internetting to find some sources of information for you.
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selfconstruct
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PostPosted: Sun Jul 29, 2012 8:16 am reply with quote
Also, take a look at vguitarforums.com for advice. There are quite a few GK DIYers there who should be able to tell you something about what you are trying to do.
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nix808
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PostPosted: Fri Aug 03, 2012 12:49 am reply with quote
Thanks Self 8D
I was looking at the innards of the breakout box,
and it seems that the GK3 is receiving +/- 18 volts.
hmm.
I see in the schematic of the GK2, that it does indeed take 7 volts.
So maybe it has quite a range of different voltages it can recieve.
I have plenty of 9 volt DC wallwarts,
do you think that would work?
Cheers
----
Smoke the pipe of peas, human beans!
http://soundcloud.com/nix808
http://rekkerd.org/nix-plugs/
Phonics Audio
^ Joined: 21 Jul 2006  Member: #113899  Location: Melbourne, Australia
selfconstruct
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PostPosted: Fri Aug 03, 2012 6:48 am reply with quote
This page http://www.vguitarforums.com/smf/index.php?topic=3624.msg267 76#msg26776
shows the GK3 circuit board. The op amps are NJM2068. The data sheet gives an operating voltage ±4V~±18V. I don't know what other components there may be which are sensitive to voltage. There are a few folks at the vguitar forums who know the gk quite well. Certainly ask there.

More information: GK Schematics http://www.vguitarforums.com/smf/index.php?topic=73.0 (You might need to be logged in to view images).

Which breakout box are you using? For dual battery usage I've seen this DIY http://www.unfretted.com/loader.php?LINK=/profs/breakout, Billbax's breakout boxes http://billbax.110mb.com/ and the Septar Kit.
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nix808
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PostPosted: Fri Aug 03, 2012 1:11 pm reply with quote
I'm using an Ubertar model.
It's very simple,
no additional electronics,
just the wiring and the battery terminals->
http://www.ubertar.com/hexaphonic/products.html
I think I will try a 9-volt power supply.
----
Smoke the pipe of peas, human beans!
http://soundcloud.com/nix808
http://rekkerd.org/nix-plugs/
Phonics Audio
^ Joined: 21 Jul 2006  Member: #113899  Location: Melbourne, Australia
nix808
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PostPosted: Fri Aug 03, 2012 2:52 pm reply with quote
OK,
I did it-
it worked!! 8DD
9v, 800ma
No more unplugging things all the time
----
Smoke the pipe of peas, human beans!
http://soundcloud.com/nix808
http://rekkerd.org/nix-plugs/
Phonics Audio
^ Joined: 21 Jul 2006  Member: #113899  Location: Melbourne, Australia
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