These various Keysight/Agilent/HP references are selected during aging but are all identical in parts and layout. Most of these references improve with age and after time many standard references will meet or exceed the performance of 002 or even the 2PPm HFL boards. The question on these eBay boards is are they ones that failed to meet factory specs. What I often wonder is in this era of JJA's why has no one built a better reference like has been done with Quartz oscillators for many decades? Cheers; Thomas Knox
> From: wpgold3...@att.net > To: volt-nuts@febo.com > Date: Tue, 27 Jan 2015 08:20:50 -0800 > Subject: Re: [volt-nuts] 3458A reference boards on ebay > > > ----- 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. _______________________________________________ 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.
