More rambling on GenRad
Since I'm on a GenRad kick today, I'm still puzzled by pricing for calibration equipment. There's a whole lot of GenRad on Ebay right now, and it divides sharply between regular 'vintage electronics' pricing and 'luxury goods' pricing. The 'vintage' pricing makes sense for hobbyists and collectors who prefer old equipment.

I noticed the difference several years ago when I bought my 1565B sound level meter from Ebay. The 1565B is the successor to the 1565A shown in previous item, and seems to have started around 1973. It's still being produced and sold now. Same functions in a smoother package, like the change from Ford Fairmont to Taurus. I bought mine for $50, and the new ones from IET are $3500. It was an excellent deal at $50. Still functions perfectly, still usable for real science.

The difference makes sense when you're buying from IET, which continues the GenRad services. You're basically paying a retainer for legal services to a company that will back up your claims of accuracy in a regulatory or legal conflict.

The difference doesn't make sense for the Ebay items seen now.

Example: Standard inductors, all fairly old-looking and all simple devices, range from $1000 down to $200. Both are supposedly tested. Some listed as 'parts only' are also around $200. None of them are from an official calibrating service like IET, so they don't include a 'lawyer retainer'. For comparison, plain non-standardized inductors from Jameco range from 50 cents up to $2.50 for a fancy one. Unlike sound level meters, there isn't any practical use for standardized inductors. You can't possibly use them in a real circuit. Even in the '30s when everything was bigger, these giant boxes couldn't have lived inside a radio. You'd only need them for QC testing if you were manufacturing fancy coils, and in that case you wouldn't be buying through Ebay.

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After detailing the meter face in my model to match the original more closely, I wondered why the meter says "DECIBELS. SOUND LEVEL METER." Seems like unnecessary clutter in a small space. When you're using the SLM, you know it's an SLM and you know you're measuring dB. The lawyer aspect illuminates the reason. Before computers and web-connected equipment, you'd create an evidentiary chain by photographing the meter along with the factory or highway you were measuring. The photograph is better evidence if the name of the tool and the meaning of the measurement are intrinsic. The upper dials are also designed for photographic clarity, so you can include the weighting and band setting in the closeup. (As shown nicely by the picture on the front of the GenRad booklet below.)

COBOL was designed with the same purpose in mind. "Overly verbose" code is self-documenting, making it easy for auditors to check what the program is trying to do.

Was this internal metadata technique widespread in instrumentation? I don't think so.

It's certainly common in other legalistic uses of photography. Mugshots always include a title card with the name and other data, often held in the suspect's hands for 'intrinsicness'. Cities used to document real estate for tax valuation with photos. Each house had an easel in front carrying the relevant info.

Skimming through GenRad catalogs, I don't see any other uses of the technique. The later 1565B, the 'Taurus', no longer has the label, and the weighting is done by pushbuttons that woudn't be easily visible in a photo. The classic Bruel & Kjaer 2203, from the same era, comes close to the same labeling and grouping for photo clarity:



Considering the added value of this design in the intended legalistic use of instruments, it's surprisingly rare.

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Separate random note: The manuals for all of these old instruments are easily available online in PDF form. I can get all the info and pix I need to "build" the models, including details of meter faces. When I was working in academic labs, whether acoustics or speech and hearing, we RARELY had manuals for old equipment. Sometimes I was able to write to the manufacturer for schematics, sometimes not. Mostly I had to figure stuff out on my own. I don't know where the manuals went; maybe grad students took them, maybe profs kept them in their offices. In either case the manuals weren't kept with the equipment.

Later and even more rambly: The 1565A struck me as unusual because the meter face is white on black. Most meter faces are black on white. The other applications of intrinsic metadata are also white on black. Mugshots and property tax photos formerly used blackboards, white chalk on black slate. More recent mugshots use 'marquees' with magnetic letters, also typically white on black. Is there a photographic reason for this? Can't find it online. Discussions of UX seem to think that white on black is more readable to the eyes, but I can't find any comments related to film photography in old periodicals. White on black is NOT more readable to my eyes.

Labels: Bemusement, coot-proofing, Metrology

  ¶ 2:48 PM