I found a suspiciously good comparison of DMM7510 vs 34470A. The DMM7510 is the clear winner. Can someone say if its plausible, or is it Keithley Propaganda?
http://imgur.com/gallery/Wbx7q
Clear winner in which aspect?
These tests are not well-grounded.
The absolute readings / uncertainty will depend on the passed time of usage, after last calibration, and this is not defined in his 'test'. The 7510 may be freshly calibrated, and the 34470A may have had last calibration one year ago. So that's an invalid comparison. In the end, both instruments are still well inside their 24h specs!
If you look closely to the StD statistics of the different DCV ranges (100mV, 1V, 10V), which is in practice identical to rms noise, you will see, that in contradiction to his final noise testing, the 34470A and the 7510 always show nearly identical StD.
He estimates the noise from the graphic display, obviously.
In this case, he could better have used the statistical function, again, w/o disturbing the cables, as he claims to have done during the uncertainty testing.
Also, a measurement on a single NPLC number gives a limited picture only.
NPLC 1 gives always noisy readings, not worth 7 digits, so NPLC 10 or better NPLC 100..500 (or averaged equivalents) would tell the interesting facts about noise performance for 7 1/2 digits.
TiN had organized a big noise comparison test, over a broad range of NPLC numbers for each instrument, which gives much more illuminative pictures on these instruments.
https://xdevs.com/article/dmm_noise/But as far as I can see, still no contribution on a 7510, what a pity.
But anyhow, the comparison to the superior 3458A might give you a better understanding of that parameter testing.
To my opinion, and experience, the real performance of 7 1/2 digits instruments in terms of noise, stability specification and linearity do not justify at all their high price, twice or four times than of comparable modern 6 1/2 digit instruments. See also my already linked 465/470 comparison tests.
Anyhow, all their user interfaces, digitizing and nice graphical features are a big pro over old boxes like the 3458A.
So, if you are crazy enough, i.e. going volt-nuts, and spend 2 .. 4k $/€/SFr, I could fully understand that
![Wink ;)](https://www.eevblog.com/forum/Smileys/default/xwink.gif.pagespeed.ic.cldandycH0.png)
If you decide to buy Keysight '465A or '470A, don't forget to order the digitizing option, the additional 2M memory (recommended for digitizing) currently is for free.
The 7510 already comes with more and better features on this aspect, I think.
Frank