[volt-nuts] What made a HP3458A so expensive

[Joe Hobart]

Bill,

Would a Josephson Junction standard need to be calibrated?

Adjusted and maybe compared, yes, but you should not need to calibrate a primary
standard?  Years ago we had HP Cesium Frequency Standards at work.  There were
primary standards and good to 4E-12 with no additional calibration.

Joe


On 1/18/2014 3:37 PM, Tom Miller wrote:
> Can you imagine what it would cost to get that calibrated?
> 
> Tom
> ----- Original Message ----- From: "Bill Gold" <wpgold3637 at att.net>
> To: "Discussion of precise voltage measurement" <volt-nuts at febo.com>
> Sent: Saturday, January 18, 2014 5:17 PM
> Subject: Re: [volt-nuts] What made a HP3458A so expensive
> 
> 
> In fact if you look at a 1982 HP catalog you will see that the 3456A was
> selling for around $3,700 and given inflation the 3458A is still a pretty
> good bargain when it was introduced in 1989.  In 1989 the 3456A was selling
> for $4,600 while the 3458A was selling for $5,900.  I wonder if there will
> 
> ever be a "3459A" 9.5 digit meter?  With a super miniture Josehpson Junction
> for a reference?
> Bill
> 
> ----- Original Message ----- From: "Tom Knox" <actast at hotmail.com>
> To: "Discussion of precise voltage measurement" <volt-nuts at febo.com>
> Sent: Saturday, January 18, 2014 1:29 PM
> Subject: Re: [volt-nuts] What made a HP3458A so expensive
> 
> 
> 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
>>