4CM - ground lifting cables

General Discussion Forum - Voice The Sound In Your Head
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Posts: 7
Joined: Sat Oct 08, 2011 12:00 am
Location: Portugal

Wed Nov 09, 2011 3:52 pm

Hello everyone.

I just bought a Series one 45 combo and I’m currently in my “getting acquainted” stage with this beast and I’m loving it. Before that I used to play through my Zoom GT9.2 multiFX (yeah, I know what you are thinking: arrrrrgh! :P ). But considering this latest AWESOME investment I have to save the buying of a few pedals for the future and get rid of (now I’m able to ear the huge difference) the more digital sound this FX unit produces.

For now I’m setting both units to play using the 4 cable method. That seems to come with a twist: the most famous HUM problem. I’ve been googling it for a few days now and came across with two possible methods to solve it: bankrupt your skinny piggy bank completely and buying a device to eliminate this hum or... ground lifting some of the cables between the amp and the FX unit.

The second seams tempting but I want in no way to damage my combo because I’ve read in some places that doing this is not advisable at all… I think I just found out that the last cable, the one that goes into the RETURN of the Amp, is possibly creating the ground loop... so, any suggestions anyone? Is it safe to disconnect that wire?

Thx in advance.

Posts: 7
Joined: Sat Oct 08, 2011 12:00 am
Location: Portugal

Sun Nov 13, 2011 1:35 pm

Hello everyone

I got an answer from one guy in a Line 6 forum (jimsreynolds) and he told me is been using a small box he built to unground two of his cables. So he said it is perfectly safe to use this method but not on all cables at once because you need to have at least one cable grounding the FX unit and the amp. Check is device in THIS POST.

From that I created my own version using two male 1/4" jacks and two female jacks. Since one wire per cable was all that I needed, I also bought a piece of car audio ground cable (3 mm of copper!) I found in my local store.

I made 2 adapters just in case but I found out that I really just need one to get rid of that nasty hum noise! Image

Here are some pics.



And here is how I'm using it:

Hope that helps someone with a similar problem.

Posts: 1
Joined: Tue Nov 27, 2012 7:54 pm

Tue Nov 27, 2012 8:12 pm


I tried your ground loop solution with POD HD500, but the hum is still there. also using 4cm method.
I disconnected the ground at the male side and used a stereo female jack on the other side dunno if thats my problem?

I only modified the cable coming from return of my amp going into 1/4 output of Pod.

Just wanna know:

1. Which side of the cable must you disconnect the ground? at the male side going into the 1/4inch output or the female side where the other guitar cable goes in?

2. Saw on the Line 6 forum guy groundlifted 2 cables - Send and Return of amp?

Hope i'm being clear enough.

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Posts: 97
Joined: Fri Oct 28, 2011 12:00 am

Wed Nov 28, 2012 8:39 am

One of the many bennefits of the RP1000... ground lift switches.

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