Guildline 9930

[acbern]

Does anybody have specs for the Guildline 9930 current comparator? Would be interested in a precision resistance measurement gear and am not finding any data to assess if this is suitable for me. Have not found any specs or manuals or other indication online.
Thanks

[Vgkid]

You might try contacting Guildline, hopefully you will have better luck than me.

[Edwin G. Pettis]

From my past dealings with Guildline, they do not seem to keep legacy specification sheets on file like many other manufacturers.  In other respects, Guildline has been quite helpful.  The 6622A-base DCC has very similar specs.  This unit appears to be very similar to the old 9930 except that it has been updated and has a fancy readout instead.  You can find the data sheet here:

http://www.guildline.com/Datasheet/Guildline6622ADatasheet.pdf

I may have a copy of the old 9930 in my archives, if I come across it, I will scan and post it here.

[acbern]

I think the 6622 is way more accurate that the 9930. I saw this data shett, but give its a new design, they certaily (also they clim it) have made many imporvements.  also, the 9930 is only 7 digits, the 9975 has 8, so it was alreayd better back then than the 9930.
if you could most data here for the 9930 that would be nice.

thanks

[Edwin G. Pettis]

To acbern,

The 6622-base model is just a digital version of the 9930 which is all analog, the base specifications of both models are the same.  Both models also had/have upgrades available to increase accuracy and also the current ranges of the base models.  The fact that the 6622 has a digital readout doesn't make it any better than the 9930 which has no digital readouts.  Digital, by itself, does not make anything better or more accurate, that seems to be a  common misconception.  Personally, I rather like analog readouts, they have no steps and better resolution in many cases, no flip-flopping digits.  I've got digital readouts on some of my instruments and often they fall short of the analog readouts.

Resolution alone does not mean anything, it does not add to the accuracy of the measurement in most cases and has inherent limitations in the digital logic.  The 9930 surpasses the accuracy requirements of any lab but a primary standards lab of very high calibre.  The 9930 and 6622 do not have built in resistance standards, they are comparators of high accuracy, you must have reference standards for these units to compare to.  They are not a resistance bridge.

[acbern]

@g pettis
the 6622AXR is typically by a factor of 10 more accurate than the 9930 at 1k and 10:1 ratio according to the data sheets (0.1ppm versus 1ppm). This is consistent, as otherwise the enhanced resolution would not make any sense. other versions of the 6622 are even more accurate (down to 0,03ppm). the 6622 cannot be compared in precision to the 9930. and the 9930 is by design a voltage comparator, using direct current comparison, it can also be used as resistor comparator. the 1ppm above is for voltage comparison and does not even include resistor-measurent related additional inaccuracies.
The 9930 is pretty time consuming to use, and despite low prices is not really a first choice, the 9975 being mainly designed as a resistor comparator has better accuracy and resolution and is faster to use.