[volt-nuts] 3458A reference boards on ebay

[Dr. David Kirkby (Kirkby Microwave Ltd)]

On 27 January 2015 at 09:16, Orin Eman <orin.eman at 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