Nice!
I'm actually planning something similar - DIY Fluke 734A, that is 4 LTZ1000 based 10V reference modules, each with 10K reference as well. For now I have all the parts for the 7V reference circuit and 10K resistors (VHP202Z) and I need to design the board. Once I finish that and the references will be aging I'll have plenty of time to figure out other circuits in the module (battery + power supply/charging, 7->10V step-up, mini-oven for VHP202Z 10K maybe, small signal relay to switch output between raw 7V and 10V, output protection etc.).
![](https://www.eevblog.com/forum/metrology/volt-reference-diyer-ltz-10v-pwm/?action=dlattach;attach=329945;image)
He must have excellent access to parts, all the oil filled Vishays, hermetic LT1013 and so on. Many months ago I requested a quote from Vishay, as I wanted to buy the LTZ1000 resistors and 10K reference (5 sets) and I got completely ignored, so I got second hand resistors (non-oil filled Vishays for LTZ1000 and VHP202Z) from eBay and the remaining parts (including LTZ1000 and LT1013 DIP8) from DigiKey.
Interesting power/voltage connection with the bare wires soldered between the mini-module and the base board. I've decided to go the 3458A reference module route and planned pin header connectors. Are bare wires better with respect to thermal EMF?