Whining noise from amp caused by Apollo

[echoless]

I want to split my guitar signal from my tuner to go direct/line in to my interface. When I do that I get a high pitch ringing in my amp. As soon as I unplug the direct cable going to my interface, the whine stops. This doesn't happen with my 65 Bandmaster. The signal is going straight from the tuner to my Apollo interface. Any ideas? There seems to be some sort of interference from my interface. Everything on the board is well powered and isolated. I cannot post a video, so the video can be seen here: https://www.reddit.com/r/GuitarAmps/comments/1c5qkdx

 

[Joe Porto]

That sounds like a ground loop. You either need to transformer isolate one of the legs of the split (p-split, hum eliminator, bigshot, etc.) or ground isolate the power to the amp (hum-x)