Problem with GR-33 to Mbox - Help!!!!

[trion12]

Hi,
I have a Roland GR-33 guitar synth that works fine for live use through my AER Compact 60 amp.
When I take the line out from the GR-33 to the LINE In of the Mbox to record with however the signal is extremely crackly and buzzy. This noise is only present when I play a note. It is not there otherwise.

I have tried LINE and Instrument input settings on the Mbox to no avail. The input levels are not overloaded as I am nowhere near the red.

When I plug the GR into my amp and then take line out from the amp to the Mbox the problem is gone.

I also tried DI out from the amp to the input of the Mbox but there appeared to be no signal getting through.

When I plug my electric guitar directly into the Mbox there is no problem.

I am at my wits end with this.
I want to use the GR to record but can't.
Any thoughts?

 

[ssscientist]

Sounds like an impedance mismatch, plain and simple.

Have you considered micing your amp as you play the GR-33?


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[trion12]

Sounds like an impedance mismatch, plain and simple.
Have you considered micing your amp as you play the GR-33?
.

Line out from the amp works fine to the Mbox so no need to mic, but the problem is it delivers mono signal - the GR is a stereo unit. Lin out on my amp also is feed after master volume so I cannot do this late at night when others are asleep.

My guess is either an impedence mismatch as you say (which I am guessing a stereo DI would fix?) or a ground loop - the GR is ungrounded.

 

[ssscientist]

It's not a ground loop.

The symptoms of a ground loop are not what you're experiencing.

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