Hello all,
I have already bought and tested several SVR from Joe Geller and reported that they are great and accurate (<5 ppm agreement to my 6.5 to 8.5 digit gear).
Yesterday I received the SVR-T which is an improved version that uses a secondary temp compensation (developed by Lars Walenius).
For more details see:
http://www.gellerlabs.com/SVR%20Series.htmI meassured/compared it with my very best calibration gear and meters.
Here is a short setup info:
>4h DMM meter warmup
man. 10VDC range with 8.5 digit and averaging
using high quality PFTE low emf cable with crimped spade lugs and crimped pure copper alligator clips
checking and making sure DC offset is well below 1µV before meassurement started
using good/stable 15.00 V linear power supply
ambient 25.1 to 25.4 °C (stable over the meassurement time)
9.999 978 7 V (seconds after turn on)
9.999 990 3 V (after 2 min.)
9.999 997 7 V (after 5 min.)
10.000 000 6 V (after 10 min.)
10.000 001 3 V (after 15 min.)
10.000 001 4 V (after 30 min.)
10.000 001 3 V (after 60 min.)
10.000 001 3 V (after 90 min.)
10.000 001 3 V (after 120 min.)
10.000 001 2 V (after about 3 h)
Whatever my real absolut meassurement accuracy might be, after only 5 min. warmup time, this little device (compared to my gear) stays easily within <0.5ppm of the stated
"Calibration: Jumper in: 10.000 00 V at 24 °C ambient" in Joe Gellers "SVR-T Calibration Paper" that came with my SVR-T.
For me that really is a great improvement to the already very good SVR!
I would be interested to hear from other SVR useres what they found out and like to see some results.
bye
quarks