i tried to connect my vx50 kraken with the QC (using load box) and i encounter hum when i use the gain 2 on the amp.
even when i placed noise gate , it wont stop the hum, only if the NG was set to 100%.
i think i saw on one post that some of the cables need to be trs to ts. is it true?
i used 4 ts to ts cables, and connected it exactly as the manual shows.
Definitely sounds like you are referring to a typical 60 or 50hz cycle from a ground loop which is a fairly known occurrence when running 4CM requiring isolation of the line between the return and the QC.
You may need a ‘humbuster’ style cable or you may need to run through a hum canceling product.
Since there are multiple ways to eliminate the hum, best bet is to Google 4CM hum and follow the various suggestions. It’s fairly common and fairly simple to resolve depending on how you power things up, and where the ground is shared.
When running 4CM and depending where I am set up, I typically use something like a Morley Hum Exterminator / Ground Loop Hum Exterminator which resolves all ground hum from amp’s fx-loop. There are cheaper solutions but I have personally used the Morley for 10+ years and it cleans everything up. Again, some have resolved 4CM hum with just a humbuster style cable (TRS to TS) it just depends on your specific amp being used and its FX loop/how its grounded.