[volt-nuts] What made a HP3458A so expensive

Tom Knox actast at hotmail.com
Sat Jan 18 16:29:11 EST 2014

Actually in spite of it's high price I feel the 3458A represents a bargain. When it was introduced in 1989 it was $5900. A price it held for decades. Although designed in 
then 80's it's accuracy is still unsurpassed.  The 8846A is much less 
expensive because it has only about a quarter the parts. With few that 
are hand selected and/or aged. And all though both meter have well 
executed designs the result is the 3458A has about a magnitude greater 
accuracy. And anyone in Metrology can attest to the fact that the cost 
of accuracy is exponential. But the thought I wanted to contribute to the dialog is the real value of the 3458A is the body 
of knowledge built around the thousands of 358A's some running 
continuously for nearly three decades. The characteristics of the 3458A 
are perhaps the best documented of any electronic instrument ever made. 
That is priceless. When comparing that body of knowledge to individual 
units I have found every 3458A is a little different and seem to each 
have their own personality. In a side note, recently I owned what appeared to be the original 3458A. I cannot remember the serial number, but it had the numbered stickers identifying the boards that can be seen in the original service manual. And it was still  working flawlessly.

Thomas Knox

> Date: Sat, 18 Jan 2014 17:41:26 +0100
> From: frank.stellmach at freenet.de
> To: volt-nuts at febo.com
> Subject: [volt-nuts] What made a HP3458A so expensive
> Well,
> the 3458A now is in production for about 25 years , and only around 50k 
> units have been sold.
> (That's an estimation by Joe Gellers series number collection)
> As the 3458A is a niche product with homeopathic series volume, the 
> development, verification/validation, special reliability engineering, 
> selection and burn-in measures, QA costs had to be paid per unit in the 
> beginning.
> To my opinion, especially the 3458A was designed mainly for military 
> requirements (Tamb 55°C). The military was willing to pay a premium (HP 
> = High Price) at that time. So HP was able to realize that price.
> All that development budget is long paid, and after end of the Cold War, 
> the military does not order so many devices anymore, what caused the 
> problems of the T&M business (finally => Keysight, urgh!).
> But as that market is tight, competitors are few, so the price is not 
> going down, instead it's increasing over the years, from $5900 to around 
> $8500.
> It would be interesting to calcualte the BOM of the 3458A.
> As they use many custom specific components, it should be relatively 
> expensive.
> There is no parameter in the HP3458A specifications, that the device has 
> to be powered constantly to meet the specs.
> Those very high 8ppm/yr. drift might apply only during continuous 
> operation.
> During power down, the LTZ should not drift at all, as the ageing 
> mechanism is driven by temperature.
> But there might be (there are indeed) considerable hysteresis effects.
> I have set the temperature of my HP3458A to ~ 60°C, I shut it down after 
> usage, and the periodical comparison to 3 other references shows a drift 
> of less than 1ppm/year.
> Frank
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