I recently purchased a used GCX & Ground Control Pro, and they're amazing when they work. Unfortunately I've had a whole bunch of almost random issues that would make them completely unusable in a live situation. Other than the GCX & GCP I also have a TC G-Major 2, and I'm currently using loops 1, 2, 3, 4, and 7. I've been prevented from hooking up additional loops due to a shortage of cabling. I'm running into the following issues sometimes simultaneously, other times not, and almost always after playing for several minutes.
Horrible noise with the 'guitar in' input while phantom powering the GCP. This noise goes away when using a different midi cable and wall wart for the GCP.
Active light on the GCX not lighting; this usually goes away after power cycling
Loops on the GCX getting 'stuck'. They stay on when switching presets, but will usually switch off via instant access.
I've tried two different midi cables both between the GCX & GCP and between the GCX & G-Major 2. I've tried swapping out patch and jumper cables for the loops as well as removing pedals from the GCX loops entirely. I've owned a GCX & GCP previously and those were bullet proof; I'd really appreciate any sort of assistance as far as getting these issues sorted out.
Issue #1 ended up being caused by a ground loop between the GCP and a metal pedalboard. Isolating the GCP solved the noise issue, but the others remain. The issue I'm having with 'stuck' loops seems to be roughly the same as the one described here: viewtopic.php?f=9&t=11910
I just powered on the system and the 'active' light on the GCX wouldn't light. None of the loops would activate or deactivate and the G-Major 2 didn't appear to receive program changes though control changes still worked. I disconnected the phantom power MIDI cable and replaced it with another cable and powered the GCP from a 9VAC / 830ma wall wart. Nothing changed with the GCX or G-Major 2, so I plugged the GCP directly into the G-Major 2, still no change even after power cycling the G-Major 2 and GCP. I then switched back to the phantom power cable and power-cycled the entire system; the 'active' light is now lit and everything works as expected.
I had the same issue from initial (phantom-powered) power-on today; active light on the GCX wouldn't light, none of the loops wanted to work, and the G-Major 2 wouldn't respond to program changes within GCP presets despite multiple power-cycles.
I tried connecting the GCP (wall-wart powered) directly to the G-Major 2, and the latter still wouldn't respond. I noticed at this point that the 'MIDI In' indicator on the G-Major 2 was not flashing when I recalled presets on the GCP. I pulled an ancient ADA MC-1 out of the closet, and the G-Major 2 immediately responded to program changes from that relic.
On a whim I went into edit mode on the GCP and tried changing G-Major 2 presets there and it worked! I exited without saving, and suddenly the G-Major 2 was responding to program changes with every GCP preset change. I then powered off and reconnected the GCX & phantom power cable, and everything is working as expected.
I'm really starting to suspect something with the GCP and would hope to hear from someone at some point. Otherwise I guess I can call Voodoo Labs...
Edit: Just had another issue where the G-Major 2 is working fine, but GCX loops aren't switching off with preset change. Instant access still works to switch loops off, but once on they're tending to stay that way despite power cycling the GCP several times. After power cycling both the GCX and GCP, loops switched properly for the first 2-3 preset changes, but they're sticking again. Power cycling the GCX & GCP again and leaving them off for a longer period of time seems to have worked and the system is stable for the time being.
Today the GCX active LED wouldn't light, loops didn't work, and 'MIDI In' on the G-Major 2 didn't flash on initial power on. After the first power cycle, the GCX still wouldn't work, but the G-Major 2 'MIDI In' did flash and control changes worked, but program changes didn't. I tried going into edit mode on my GCP preset, but changing the PC number there did not affect the G-Major 2. After the second full power cycle, the G-Major 2 worked as expected, the active LED was not lit and some of the GCX loops worked while others did not. After the third full power cycle the active LED wouldn't stay lit, but everything else seemed to work. After power cycling the entire rack a fourth time, everything seems to be working. Is there anything I can do with these, or did I get burned on a couple of lemons?
I've noticed that for the last several days the system essentially never powers up in a usable state; it typically takes several power cycles over the course of 5-10 minutes for the system to power on and work as expected. Once the system is working, any issues that occur seem to be resolved by a single power cycle of the GCX & Ground Control Pro.
On a whim today I powered on the Ground Control Pro with the 9VAC wall wart and left it that way for 20-30 minutes. I then disconnected the wall wart, reconnected the phantom power cable, and powered on the rack. Everything is working as expected, so it appears that there's a warm up or temperature issue with my Ground Control Pro. Is anyone able to help me get this fixed, or am I stuck junking the GCP and finding another one?
I use a Pedal Power AC or a MXR 403 and use its AC power.
If you use a DC power supply off a Pedal Power 2+, you need to use outputs 5 or 6 and have the dip switch away from normal, this gives unregulated power around 12v when tested.
Hope this helps, get back to us with what your power supply is for the GCX.
Cheers
GCPro, GCX, Pedal Power 2+, Pedal Power AC.
And some other stuff.
I'm using the wall wart that came with the GCX. I recently borrowed a friend's Liquid Foot, and the GCX has been 100% reliable and stable with that, so I'm pretty sure the problem is with the Ground Control Pro. The only issue I still see while using the Liquid Foot is that the 'active' LED on the GCX doesn't stay lit; otherwise everything else works like I remember and expected.
