Hello! I have a problem with ground noise when using the 4 cable Method! Here are the steps of building my sound chain: 1) I plug guitar into Pod's Guitar Input 2) In my preset there are no effects but Fx Loop right after the mixer 3) Input Settings of Pod are: First Input Channel - Guitar, Second Input - Variax 4) I achieve the Unity Gain with mixer settings, with 1/4 Out switch set in Amp position and with Fx Loop Mode set in Stomp mode, so Pod HD500x does not change the sound of my guitar before the external Amp at all, just like if I plug guitar directly into the Amp 5) and when all connections are made there is ground noise occurs! It is not from guitar pickups, it is between Fx Loop Send and Amp Input! I have experimented with plugging my guitar directly Into the Amp, so my guitar signal flows this way - 1) Amp in 2) Amp Fx Send to Pod FX Return 3) Pod Output to Amp Fx return - and there is no hum at all! Even with a lot of Gain on the lead channel of my Amp! But in that case only effects after Fx Loop in Pod's Preset are actually taking a part in sound changing (Delays, Reverbs etc) So, the problem occurs between Pod Fx Send and Amp Input What should I do to eliminate this issue? Thank you!