I had built a couple Cracks and a Quickie previously and found the S.E.X. to be quite a bit more involved. Not harder, just more pieces.
When I went through the resistance checks upon build completion, everything was spot on. Then when I went through the voltage checks, all voltages were very close until I got to H2, H4, H5 and H7. The problem was a large blob of solder providing contact with one lead of the 5W resistor and the mounting nut sitting 1/8 inch from it. Easy to diagnose as I noticed it when I soldered in the resistor, but thought I had removed the blob.
Now that that's taken care of, the amp sounds fantastic. Zero noise of any kind with headphones, even at max volume (no signal applied). So I hooked the amp to my KEF LS50s and it sounds great. Not trying to shake the house, but Norah Jones sounds wonderful.
Now for my recommendation. Solder the .1 ohm 5 Watt resistor to the terminal strip before installing the terminal strip. It may be out of sequence, but if I built another S.E.X. amp, that's what I would do. Couldn't hurt.
Source: Lumin D2 with SBooster power supply, 2tb SSD attached to Lumin, Pre: Moreplay, Amp: Bryston 2bSST, Speakers: Joseph Audio RM22XL. Setup in large, well treated dedicated listening space.