Helix LT Changing channels on external head issues... in Helix Posted 7 hours ago I saw on a you tube video how you can get the Helix LT to change channels on a head. I've got the LT Ext Out 1/4 going to a Marshall JCM 2000 50 watt head, which is capable of channel switching. As soon as I plug a guitar cable from the Helix Ext out 1/4 and go to the Marshall 1/4 that is for channel switching, I get a loud hum that won't go away. I figured out how to make the channels switch, but I get a loud POP every time I go from the clean snapshot to the dirty snapshot. I don't get any hum when I use the switcher that came with the amp. I tried a standard guitar cable and a cable that came with a single button switcher pedal...same loud POP with both. Also a really weird sound changing from Clean Snap Shot to Dirty snapshot. Thanks for you replies.