GCX hum issues

Q & A for building and interfacing your rack gear with Ground Control Pro and GCX-based systems.
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Donnie St. James
Posts: 34
Joined: Sat Feb 01, 2014 2:29 pm

GCX hum issues

Post by Donnie St. James » Fri Jan 23, 2015 7:54 am

I'm running a GCP/GCX combo with my 5150-50 watt. The GCX is set up like this:

Loop 1 - Eventide Modfactor

Loops 2 through 4 in amps FX loop

Loop 2 - Eventide Timefactor
Loop 3 - TC Electronic Spark mini (for clean channel boost as anyone with this amp will understand)
Loop 4 - TC Electronic Spark mini (for lead boost)

Nothing in loops 5, 6, 7, or 8

I have the Eventides both plugged into a Furman power conditioner as well as the amp, GCX, and a Power Pad II by pedal pad. The TC Sparks are being powered by the Pedal Pad as they cannot be powered by battery.

I get a loud hum when the Sparks are being used, bypassed or not. If I remove them from the amps FX loop, the hum is gone. Here is what I have tried so far:

Removing Sparks from the chain completely and using 1 cable to connect amps FX send to return to each other - no hum.
Plugging the pedal pad into a completely separate outlet (not on the furman) with the pedals in the chain as normal - hum.
Connecting the amps FX loop to an empty loop (loop 7) on the GCX with the Sparks still powered on - no hum.
Using both Guitar In and Feed thru - hum.

I have not had this issue before. I used a G System (4 cable method) with a Spark mini connected to it and before that I just had stomp boxes direct to the amp and amp's FX loop. I had a Micro Amp in the amp's FX loop and never got this noise. The pedals were always powered with this same Pedal Pad.

I saw the humfrees people have suggested on here, but not sure if that will take care of it.

I'm open to any and all suggestions as I would really love this to work out for me.

Thanks.
DSJ

nyteowl
Posts: 1389
Joined: Mon Jan 25, 2010 8:53 am

Re: GCX hum issues

Post by nyteowl » Fri Jan 23, 2015 10:39 am

Just spitballin' here, but could you possibly have a bad cable..?

Also, have you tried swapping out the loops and placing the Eventides after the Sparks in your signal chain?

All the HumFrees will do is isolate your GCX from your rack, which won't do anything to prevent hum from your pedals. Something from the Ebtech Hum Eliminator product line would be more applicable, but in my experience they tend to be real tone suckers. Of course, they may have improved with age; it's been ten years since I've used one.
For Sale: Original DMC GCX in Excellent Condition ($275) and a far more versatile SoundSculpture GL also in Excellent Condition ($1750). Free CONUS Shipping.

Donnie St. James
Posts: 34
Joined: Sat Feb 01, 2014 2:29 pm

Re: GCX hum issues

Post by Donnie St. James » Sun Jan 25, 2015 7:06 pm

Thanks for the reply, Nyteowl. I figured out the problem and I'm not sure how to fix it. It seems when the GCX and the Furman power strip (which is the M-8X2) are next to each other I get the hum. I removed the GCX from the rack and plugged everything in exactly as before and problem was gone. I put it back in and it's back. I then took the Furman out of the rack and set it aside and turned everything on and all is good. I then moved the Furman closer to the GCX and the closer it got, the louder the hum.

Aside from separating them in a rack, are there any other options? I don't need much rack space as those are the only two things I have racked. I will have my pedal in there as well but only need minimal space for them.

Any suggestions are greatly appreciated.

TIA,
DSJ

Donnie St. James
Posts: 34
Joined: Sat Feb 01, 2014 2:29 pm

Re: GCX hum issues

Post by Donnie St. James » Sun Jan 25, 2015 8:45 pm

Ok, scratch that last post. I found out the culprit. Those damn Eventide power supplies. They are causing noise when next to the send/return FX loop cables. I guess I just have to find a way to keep them away from everything. If there are any suggestions, again, I'm all ears.

DSJ

nyteowl
Posts: 1389
Joined: Mon Jan 25, 2010 8:53 am

Re: GCX hum issues

Post by nyteowl » Mon Jan 26, 2015 10:01 am

It's always a good idea to not let any audio cables run parallel to power cables, and if you have to cross them, do it at a 90º angle.
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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