[volt-nuts] What made a HP3458A so expensive

[Tom Knox]

A Josephson Junction is not a Cesium Standard. It is not quite to the Plug and Play level. And takes a few racks worth of space.
Operation and Maintenance is more difficult then most calibrations. But big advances are being made. 
At some point in the not to distant future I foresee JJ arrays being configured as not just a references,
but full function calibrators with direct quantum synthesis of any DC, AC, Ohms, and Current. Sam Benz
has lead much of this research. http://www.nist.gov/pml/div686/devices/voltage.cfm 
I am amazed that greater advances have not been made in zeners references or more specifically their packaging


Thomas Knox



> Date: Sat, 18 Jan 2014 17:44:43 -0700
> From: nova at npgcable.com
> To: tmiller11147 at verizon.net; volt-nuts at febo.com
> Subject: Re: [volt-nuts] What made a HP3458A so expensive
> 
> 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
> >>
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