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Ground Loop Hum, POD HD PRO 4 Cable Method with Mesa Mark V
by Mattchalkguitar on 2012-06-06 07:24:02

Hi there,

I recently purchased a pod hd pro  to use in the 4 cable method with my mesa mark v. I have tried lots of things to try and stop the ground hum, but to no avail. So far i have tried:

Ground Lifted Cable (removing the ground on 1 or more leads in the fx loop)

ART Cleanbox II (Ground hum remover box)

The only soluotion I have had is the following (I'm not satisfied with its safety):

2 Pin powerlead (euro) into UK adapter

1 Ground Lifted lead in the FX Loop.

Im am based in the UK my rig is the following:

Mesa Mark V Head

Voodoo Labs Ground Control

Voodoo Labs Control Switcher

Samson Powerbrite PB15

POD HD PRO

(I'm currently using a G Major 2 due to this problem with the POD)

All leads are Cordial / Lynx audio and are high quality OFC Cable.

If i use a UK 3 pin plug or plug it via IEC into my power conitoner I get awful hum no matter what I do, if I use ground lifed leads or the cleanbox still no solution. The only soloution is a combination of 2 pin Euro lead into the UK adaptor + one of the ground lifted leads.

Any help would be much appreciated as this is driving me mad!

Thanks
Matt



Re: Ground Loop Hum, POD HD PRO 4 Cable Method with Mesa Mark V
by markkessels on 2012-06-06 13:38:13

ONLY use your Mark V. Put your guitar in it. Does it hum?

If no, put a lead from send to return. Does it hum?

Try adding the ground control stuff one by one.

Maybe put your rig through the powerbrite.

Does it hum with the g major in the fx loop?

Check your cables...



Re: Ground Loop Hum, POD HD PRO 4 Cable Method with Mesa Mark V
by Line6david on 2012-06-06 18:00:40

+1 to markessels,

We need to determine if the issue is a cable, AC strip, pedal or bad power in the space you are using it in. break down the rig and try each component one at a time. This will help you determine what is causing the loop. Also, is everything plugged into the same power strip and a single AC outlet?

If you need more help, please respond to us directly:

http://line6.com/account/tickets/view

Thanks,

David



Re: Ground Loop Hum, POD HD PRO 4 Cable Method with Mesa Mark V
by jimsreynolds on 2012-06-07 03:04:34

It all sounds very much like a ground loop from what you describe.  These can be a pain in the rear end to track down and it gets harder with more gear in the setup. 

My hookup is was fairly simple:   JVM Amp + HD500 in 4CM - no other devices.  I had a killer hum that got fixed using two ground-lifted cables to connect the HD to the loop on my amp.  It sounds like you have tried that through already.

You have the voodoo labs switching/controllers too.   What What happens if you hookup  The Mark V and the POD using the ground lift cables but leave the Voodoo labs gear unplugged?  

You should be able to beat this by stripping things down as Mark and David have said and piecing things back together one step at a time.  Hum can creep in through Midi cables, footswitch cables (using your control switcher) and other hookup cables also so suspect everything initially.



Re: Ground Loop Hum, POD HD PRO 4 Cable Method with Mesa Mark V
by Mattchalkguitar on 2012-06-07 04:59:07

Hi David,

Thanks for getting back to me - All products are connected to the Samson Powerbrite. I have tried every combination and taken every product in and out one at a time - as soon as the POD HD PRO is removed - no hum. My TC Electronics G-Major 2 works perfectly and has done for the last 3 years i've had it in this setup with no ground loop issues.

The hum disappears when I remove the software FX LOOP on the POD HD, it also goes when I disconnect the pod from the input of my Mark V and plug the guitar into the front of the amp directly the hum can also be turned up and down with the POD HD PRO's master volume.

I have removed all of the Voodoo Labs gear, the powerbrite, tried different outlets in the house, different houses and STILL the hum persists. Like I say the only solution is using one ground lifted cable and the Shucko power lead that came with the pod (I purchased from thomann, so I got sent a euro (shucko) IEC) into a euro to UK travel adapter, but like I say Im not satisfied with this setup.

I've spent about a week doing nothing else but trying to get this to work!

I'll submit a support ticket soon.

Thanks

Matt



Re: Ground Loop Hum, POD HD PRO 4 Cable Method with Mesa Mark V
by Mattchalkguitar on 2012-06-07 05:00:48

Thanks for the replys guys - as you can see in my reply to David I have tried all those things - but to no avail!

Cheers

Matt



Re: Ground Loop Hum, POD HD PRO 4 Cable Method with Mesa Mark V
by Mattchalkguitar on 2012-06-07 05:01:00

Thanks for the replys guys - as you can see in my reply to David I have tried all those things - but to no avail!

Cheers

Matt



Re: Ground Loop Hum, POD HD PRO 4 Cable Method with Mesa Mark V
by rphenson on 2012-06-07 07:11:12

I had a problem with my HD500 and power speakers humming (ground loop) until I plugged them into the same power strip.  I understand you have already tried this and more.

While you shouldn't have to resort to it, you may be able to stop the problem with an audio isolation transformer between your HD Pro and the other equipment.  Each audio input and output connecting the HD Pro to other equipment (other than your guitar/bass) would need an isolation transformer.  The isolation transformer is basically a 1:1 ratio transformer that separates the ground on the HD Pro from the ground on your other equipment.  This is a less than ideal fix, since the isolation transformer may produce some unwanted degradation in the tone, but It might serve to at least verify that there is a problem with the grounding in the HD Pro.  In the US, very cheap isolation transformers can be purchased at retail electronics stores (Radio Shack where I live).  Again, this is probably not a good permanent fix.

It does seem that the HD series is more susceptible to ground loop problems than other equipement I have worked with.  I live in a relatively new home with uptodate wiring, but had a ground loop problem until everything was connected through a common power strip.  I have used lots of other audio equipment in my house plugged into different receptacles without having to take this step and not had any problems.



Re: Ground Loop Hum, POD HD PRO 4 Cable Method with Mesa Mark V
by ibanezman2012 on 2012-09-14 01:57:23

So i tried to post this once before and ran out of session. so her's the amended version. Try placing the mesa's preamp within the effects loop of the hd. also, be mindful of WHERE in the chain you are placing things, i.e. place your volume pedal first, then other dynamics pedals, then the hd loop (with the mesa's preamp "inside of it", etcetera, and so on. This will enable you to use the amp's effects loop for other processing if you so desire. You might also try a line buffer in front of or at the back end of the entire chain. I fi d line buffers to be a lifesaver if one can afford them. Also, a personal discovery of mine is that the less crap i put between me and my amp, the better my result is. As i said i don't know if this will help or not. On another note, one must remember that whatever mesa amp you ha e, it's old technology that makes it work. Sometimes old and new technology don't work so well together. Basically i also wanted to say that in my opinion the hd works best as a standalone unit, with second best (though not by much) using the 4 cable method as described by line 6 on their website. It's worth checking out cause it ROCKS!!! I hope this helps you bro.



Re: Ground Loop Hum, POD HD PRO 4 Cable Method with Mesa Mark V
by meambobbo on 2012-09-14 13:04:09

my advice would be to plug the Pod cable into a 3-prong to 2-prong converter and plug that into your power strip.  You are effectively not grounding the Pod, eliminating the possibility of a ground loop AFAIK.  May introduce the greater possiblity of shock, but with everything else grounded I don't think it'd be a big deal.




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