Well i think i goofed in the above measurements ....
When you use 6.5 digit you can't be sloppy ...
Above i had all 3 meters connected to the REF at the same time , and was using 3 different wire sets.
I have just dropped that approach , and am now only "the same" wireset , and connecting one meter at a time to the REF
The results seems a lot more as i would have expected.
LM399 / 22.3 C :
2015 : 06.83068/69
3401a : 06.83070/71
3478a : 06.8314
Geller / 22.4 C:
2015 : 09.99998
3401a : 09.99993
3478a : 10.0008
I have to get my 3488A switches going , and add an automatic Temp. measurement to the measure set.
But now both the 2015 & the 34401a seems so be close to the expected 10v.
The 3478A (ebay) has always been "high" , and i wonder if i can calibrate "just the 10v" my self.
I don't have any other decent references ready yet , my EDC E100C isn't restored yet , and it will still only give 10v & below.
I think the 2015 is the one i have to call my "REF meter" , as it was calibrated on 20-may-2011.
I can hope my arriving 3457a has a recent/valid calibration (ebay seller wrote ... pulled from a working lab) ,
but i don't expect much.
Wonder what a 3457a cal costs here in Denmark or Germany.
Ohh ... I wonder why the 2015 is higher than the 34401a on the Geller , and just the opposite on the LM399
![Confused :-//](https://www.eevblog.com/forum/Smileys/default/confused0024.gif.pagespeed.ce.5xOqKkq0Co.gif)
/Bingo