Hi guys, I am also watching this thread with interest. I became infected with volt-nuttery many decades ago, fresh out of uni, in the standards lab for (then) Australia's big Telco. One of our workhorses was a newish 335 which I loved using - unlike Charles' experience, we all found the last digit to be "useful" and certainly useable in doing various transfers and comparison (not absolute accuracy, of course). Many years later I scored a 332B/AF ( Mosfet chopper, top three digits adjustable, and ref amp replaced (apparently) with LTFLU-1CH) but of uncertain provenance, and it has been one of my pet projects over the years. Again, I find the last digit fairly quiet when looking at the delta between it and a bank of Weston cells with a microvoltmeter. Well. Quiet in the short term, but the unit does have issues at a 1-5 minutes time scale with random twitches and jumps, This is all part of my "project" to sort out. So far I have made a number of modification to reduce the power consumption ( now around 11W idle down from around 32, with a consequent reduction in temp rise and warm-up time) and am now turning my attention to the precision bits. I realise that some my just need a good calibrator without futzing around - and I am sure that the advice to "go 5440" is the right advice for many. Sadly, in Australia, there don't seem to be a bunch of people with 2 5440's they want to be rid of! But I'm having lots of fun with my 332.
Roman -----Original Message----- From: volt-nuts [mailto:[email protected]] On Behalf Of David C. Partridge Sent: Monday, 10 July 2017 1:03 AM To: 'Discussion of precise voltage measurement' Subject: Re: [volt-nuts] Fluke 332B Thanks Charles, Dave -----Original Message----- From: volt-nuts [mailto:[email protected]] On Behalf Of Charles Steinmetz Sent: 09 July 2017 13:31 To: Discussion of precise voltage measurement Subject: Re: [volt-nuts] Fluke 332B David wrote: > When running through the calibration of the unit last night, I found > that it was really quite noisy > > So, is it worthwhile to replace the chopper amplifier board and > replace electrolytic caps or would that just make marginal > improvements > > If it would still be an unstable, noisy brute after I finished that, then I > think I'll put it on eBay ... My experience with these extends back to when they were new. They are definitely noisy even when they are in perfect condition, and this many years on they tend to be quite unreliable even if they have been thoroughly gone through. Also, something I haven't seen mentioned much is that the last decade (LSD) is purely for decoration. The accuracy of the 332 on its best day is worse than one division of the second-last decade. In my expeience, the original choppers work very well unless they are broken. I do not expect that a chopper-stabilized op amp would provide meaningful improvement. I advise passing on the 332A/B/D and holding out for a 5440B. You will not be sorry. Best regards, Charles _______________________________________________ volt-nuts mailing list -- [email protected] To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts and follow the instructions there. _______________________________________________ volt-nuts mailing list -- [email protected] To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts and follow the instructions there. _______________________________________________ volt-nuts mailing list -- [email protected] To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts and follow the instructions there.
