Build two PX-References these days. I used V2.2 boards with ltz1000a and hifi resistors, they are RNC90Y types of 13k, 1k, 2*75k, 120R. For the R4/R5 divider, simply but careful i combined them together with shrinking tube and a little thermal grease between, and bend solder feets together without stress them to much at the place they go into the resistor.
One Reference has ltz1000a 9636 from hifii. As i can see, it is very stable after the first burn-in about 60h, although the can looks a little bit damaged and has no gilded pins, but luckily they are long enough. For this one, i have a Hammond 1590B, but not drilled holes for the Pomona binding-posts in the moment. (edit: in the moment no pictures from this one)
For the other one with new ltz date 1750, i used a TEKO372 steel sheet housing from Reichelt
TEKO-372. Normaly this housing, dimension 83 x 50 x 26 mm, is too little for binding posts at two sides and this little PX-PCB with components, but it would be nice if it worked anyway. Without binding posts, it even fits inside the Hammond 1590B for better steel sheet shielding and nevertheless reasonably airtightness, as we can see on one of the pictures.
Because the PX-pcb doesn't really fit inside the TEKO-372, i cut 2 mm at a suitable edge of the pcb, carefully without damaging any traces.
Sorry cellular, now your github url isn't visible anymore... But the result is awesome!
Underneath the pcb i put one of this Digi-Key typical silicat-sacs, let's see if that helps a bit, and above one cotton pad before i closed the lid. I haven't had such little, precise, and really low-noise reference before.
More will follow...
Thanks cellular.