Currently Being ModeratedMay 1, 2012 8:51 PM (in response to VinnySem)Re: HD500 4 Cable Method Ground Loop Hum
Yes, I had a similar problem with my Marshall JVM using 4CM. The trick for me was to remove some of the ground connections between the POD and the amp .. you should only need one connection.
You can either try a transformer (e.g. Ebtech Hum Destroyer or Behringer HD400) or simply break the ground connection on some of your cables. I went with the broken ground connections and this was very effective for me.
Full details in the thread here, including a simple diagnostic using some spare jacks and croc-clip test leads - http://jvmforum.com/phpBB3/viewtopic.php?f=7&t=5610.
Currently Being ModeratedMay 2, 2012 10:28 AM (in response to jimsreynolds)Re: HD500 4 Cable Method Ground Loop Hum
Thanks Jim. I read your well written post regarding 4CM setup, and followed that step by step. I do have an Ebtech hum eliminator, when I connect it all my signal disappears. I don't know what I'm doing wrong.
Currently Being ModeratedMay 2, 2012 12:16 PM (in response to VinnySem)Re: HD500 4 Cable Method Ground Loop Hum
Ooh ... that ain't right!
I used the Behringer HD400 which I think is pretty much the same thing. Where are you connecting the eliminator?
I hooked mine up as
Amp FX Send --> Behringer Channel 1 input
Behringer Channel 1 Output --> Pod FX Loop Left Return
Pod 1/4" Left Output --> Behringer Channel 2 input
Behringer Channel 2 Output --> Amp FX Loop Return
And that worked well. If that does not work for you then consider the test rig with jacks and hookup cables as an alternative. It is pretty cheap. For example in the UK, the jacks here are suitable at £1.89
And the a set of test clip leads here at £5.99 (though you only need 2).
If the test hookup works then it doesn't take much to modify some cables too. I have been using cables with the grounds removed on my JVM for a while now.
Currently Being ModeratedMay 2, 2012 6:49 PM (in response to jimsreynolds)Re: HD500 4 Cable Method Ground Loop Hum
So, turns out that one of the patch cables I was using with the Hum Eliminator was bad, swapped it out and voila! Sound and no hum!
I wonder, could one or more of the cables I am using also be bad, introducing the loop hum?
Now the "fun" part begins, patch creation!