Just note, stock tubes in the Darkvoice are terrible. They need to be rolled for it to sound decent. And even still it's meh. Valhalla 2 is worth the extra $150 for sure. It is just a far better Amp.
Gsh2000I replaced the stock power tube with a RCA 6AS7G and it works great
I still get the hum, but its not audible once music starts playing. I am hoping the hum will go away once amp and tubes go through the burn-in process