----- Original Message ----- From: "Dr. David Kirkby (Kirkby Microwave Ltd)" <drkir...@kirkbymicrowave.co.uk> To: "Discussion of precise voltage measurement" <volt-nuts@febo.com> Sent: Tuesday, January 27, 2015 2:24 AM Subject: Re: [volt-nuts] 3458A reference boards on ebay
> On 27 January 2015 at 09:16, Orin Eman <orin.e...@gmail.com> wrote: > > There is a seller letting a slow trickle of them out there... they seem to > > be going for about $165. The current batch of two is around $100, but will > > probably be bid up. > > > > I just received one that I won. Seems to be working fine after a quick > > breadboard lashup. I'll be making an enclosure for it next. > > > > A little expensive IMO, but given the trouble getting the precision > > resistors to DIY with the LTZ1000A, probably worth it. > > > > Orin > > Orin, > > What do you intend doing with it? > > I was thinking about getting one of those, with a view to putting it > in a box with a couple of terminals to have something to compare with > my 6.5 digit 3457A. But what put me off is a lack of knowledge in > knowing how to convert a 3458A reference board into a boxed unit with > a known output voltage at the terminals. How would I avoid / control > thermal EMFs? > > I'd be interested to hear what your plans are for it, and how you > intend tackling those issues. > > Do you know what the difference in the reference is between a standard > 3458A (8 ppm) and the high stability option 002 (4 ppm) model? I'm > guessing the chips for the option 002 might be the top performing > ones. I wonder if there's any way to tell from your board if it came > from a standard 3458A or a 3458A with option 002. > > Dave Dave: The 002 reference boards have another label on them marked 03458-66519 which overlays the etched number on the PC board. As a matter of fact see the new listing on evilbay 271754789913. The super ultra stable 2ppm is marked 03458-66529 to the best of my knowledge. Bill > _______________________________________________ > volt-nuts mailing list -- volt-nuts@febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts > and follow the instructions there. _______________________________________________ volt-nuts mailing list -- volt-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts and follow the instructions there.