[volt-nuts] Valhalla 2703 AC calibrator

[Mark Sims]

So far the thing is working even better than it has any right to.   I ran it past all three of my 3458A's and it is within less than 0.005% (spec is 0.02%).  And that is with no calibration on it. Drift has been pretty much non-existent (the 3458A's seem to drift more than the 2703 over a 24 hour period).  That is rather surprising compared to my 2701B DC calibrator which is not the most stable thing around.  They both use an LM399 as their reference.

The nice thing about the 2703 (like a lot of older tech stuff) is that there is no secret jiu-jiu in it.  All off the shelf parts and freely downloadable service manual (SR can go suck eggs).  The only "custom" parts are the firmware EPROM (soon to be backed up) and the sine-wave generator lookup PROMs (easily duplicated).  And a couple of power supply transformers.