GCP & GCX to Audiobox to 2 Amps

Q & A for building and interfacing your rack gear with Ground Control Pro and GCX-based systems.
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GCP & GCX to Audiobox to 2 Amps

Post by Seth008 » Wed Mar 27, 2019 8:13 pm


I am attempting to do the following:

GCP --> GCX --> Audiobox --> GCX --> AMP1 & AMP2

I have been following the manual on how to Combine Multiple Amps, but something is not correct with this documentation as I have performed what is in the diagram and am still coming up with nothing but static. Presently, this is my configuration:

GCP --> GCX (Midi Port) **Works**
GCX Front (Guitar In)
GCX Back (Guitar Out) --> Audiobox In
Audiobox Out --> GCX Channel 1 Return
GCX Channel 1 IN --> GCX Channel 2 IN
GCX Channel 1 SEND --> AMP #1
GCX Channel 2 SEND --> AMP #2

I do not think the GCX Front Guitar IN port actually transfers the sound to the GCX Guitar OUT port on the back as this does not work in any configuration I have tried. The documentation on both the GCP and GCX is absolutely atrocious, but the devices are sound and solid so I purchased them knowing this from the get go. Any help with this would be much appreciated!

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Re: GCP & GCX to Audiobox to 2 Amps

Post by JohnClark » Thu Mar 28, 2019 10:56 am

Sorry you are having troubles! Your described loop connections don't seem to route any audio signal to the amps, but you should have signal into the AudioBox.

I suppose the first step is to confirm that the Guitar In/Out path is in fact working. You can test by doing the following...
1. Guitar to GCX front panel Guitar In.
2. GCX rear panel Guitar Out to Amplifier Instrument Input.
With the GCX powered on, you should hear the guitar from your amp.

If the above test works, then we should be all good to go on to the next step. In general, if you were to use Loops 1 and 2 to switch the amps, running both amps would be done as follows...
1. Guitar to GCX front panel Guitar In.
2. GCX rear panel Guitar Out to GCX Loop 1 In.
3. GCX rear panel Feedthru to GCX Loop 2 In.
4. GCX Loop 1 Send to amp #1 Instrument Input.
5. GCX Loop 2 Send to amp #2 Instrument Input.
This will allow you to do A/B/Y sort of setup. Whatever Loop is Active will route sound to that amp. So you can have either amp, both amps, or mute all sound by turning both Loops Off.

What exactly do you want to do with the AudioBox? (I assume this is the PreSonus AudioBox USB Audio Interface?) Will it only be used to record, or will it also sometimes be a playback device?
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Re: GCP & GCX to Audiobox to 2 Amps

Post by nyteowl » Thu Mar 28, 2019 12:26 pm

I can empathize with your situation, as I was totally lost when I acquired my first GCPro/GCX system, but fortunately there are a lot of very knowledgeable people on this board, so help isn't hard to come by.

Like John, though, I'm also curious as to the purpose of the Audiobox, and why you positioned it at the head of your signal chain.

For Sale: Original DMC GCX in Excellent Condition ($275) and a far more versatile SoundSculpture GL also in Excellent Condition ($1750). Free CONUS Shipping.

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Re: GCP & GCX to Audiobox to 2 Amps

Post by Seth008 » Thu Mar 28, 2019 2:23 pm


Thanks for the response! To answer your questions:

- Testing the guitar input front panel does work with the configuration you mentioned!

- The PreSonus Audiobox USB is used for recording and for utilizing BIAS FX, BIAS AMP, etc from my computer. So in a manner of speaking it will be used as a playback device for different BIAS rigs I create in the app.
- At some point I will get a tablet and use that for BIAS, but for now it is all I have and I will be using the GCP to switch between BIAS rigs when all said and done.

I also have stomp boxes which I will eventually add to the rig as well, but for now just wanted to setup a sort of bare minimum of what I need while I adjust to using this type of setup and can learn how everything connects together as I go along. In the next few I will attempt the below configuration you laid out and will let you know the results. Thanks again for the assist on this!

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