Just to put another twist on this, the problem I was having with channel imbalance came back intermitantly, so I started trying to figure it out with Lukasz again. I am embarased to report that the problem I had is/was due to a quad of tubes that had a bad tube in the mix. This Quad was a NOS set from the 70s, not the factory supplied tubes. I have no tube tester so I was swapping tube sets out and discovered the bad tube by accident. This makes sense as Lampi reported they could not duplicate my issue on the bench, but did repair some shipping damage I caused by shipping it back. I am now once again in love with my Horizon and my system overall. The invitation to roll all kinds of compatable tubes in the Horizon is a wonderful thing, but you need to know a wee bit about tubes before you start to roll tubes in it! When my Audio friend in Seattle learned I was getting a DAC/PRE with 7 tubes of three different types and I asked him for a tube education, he didn't know where to start. I'm learning and it's fun!