I bought this owner completion Pass balanced Zen pre amp from someone here who owned it briefly and moved on to something else before finishing it themselves. It only had one pair of SE inputs connected. Thanks to Fred for some Zen tips and suggesting I turn the pre amp board 90 degrees. Relocating the pre amp board allowed for shorter and better routing of wiring.
I also moved the attenuator/selector forward slightly as clearance was tight by second pair of outputs. I just left it with one pair of balanced/SE outputs. I did connect the two balanced and four SE inputs to the selector. Input/output grounds are star grounded at their respective side of board. I just used twisted pairs from an old chunk of Cat5 cable I had laying around.
I also wanted a chassis to chassis ground. Rather than look for different umbilical connectors, I eliminated one pos and neg power wire from the original two each to the pre amp board. That freed up two pins and one was used for chassis to chassis ground. I still need to get some parts to secure the toroidals.
It sounds really good for a simple design with no exotic parts (but the boards do have quality parts). It is quiet, no hiss or hum at full volume no music playing, no spikes/pops from speakers when changing sources. It doesn’t knock my recapped/tuned up Krell KSL pre off the rack, but it is worthy of a really nice enclosure and upgrades.