Hello! Getting back into my headphones hobby after not using my equipment for a few years. I have the CTH+SDAC from Massdrop and the 6xx. Plugged everything in but I'm getting no audio on the front jack. Back jack works, so I assume DAC/power is fine but I'm doing something wrong with the AMP. I've played with the input presses/extended and volume knobs and nothing... Tube lights up the way I remember it used to and gets hot. Any ideas how else I could fix this? Really missing using it these days. Thanks!