[volt-nuts] Valhalla 2703 AC calibrator

gbusg gbusg at comcast.net
Fri Apr 1 04:35:56 UTC 2011

That's great agreement between 2703 and 3458A's.

0.005% at what voltages and frequencies? (Of course 3458A ACSYNC specs are 
worse than 0.005% at mid-band audio, although better than the 2701B's 
specs.) You're setting your 3458A's to ACSYNC mode, right? ...and running 
ACAL ALL first?

Thanks for the hint about the online manual at the Valhalla site. I 
downloaded it.

Like you, I too have a 2701B DC standard. Like you say, it's not the most 
stable thing around. You can spend a lot of time adjusting and re-adjusting 
it to "perfect" it, but it has some pretty obvious temperature coefficient 
effects, and long-term drift.

Thanks for the reports.


----- Original Message ----- 
From: "Mark Sims" <holrum at hotmail.com>
To: <volt-nuts at febo.com>
Sent: Thursday, March 31, 2011 10:09 PM
Subject: [volt-nuts] Valhalla 2703 AC calibrator

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 

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.
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