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
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@freenet.de
To: volt-nuts@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
volt-nuts mailing list -- volt-nuts@febo.com
To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts
and follow the instructions there.
There is one other issue with the stability of the LTZ1000A besides aging.
In leaving it unpowered for a long period of time the junctions are not
biased and if there is any contamination present from the fabrication of the
wafers, the free contamination ions can migrate back to the junctions and
change the parameters for a time after being powered up again until the
biasing causes the free ions to move away from the junctions again. I am no
semiconductor fab engineer but I have observed this when testing
semiconductors. The breakdown voltage can change, being lower after a long
shutdown period and then be higher after it has been under power for some
period of time. One would hope that LT would be very careful on their
products, but I have seen that when wafer fab is moved to China the product
degrades because of the dirty environment that exists there, even though
measures are taken to avoid this. When fab occurs in the USA there is a
much better chance that the whole fab process will be much much cleaner.
I do know a lot about final testing. I have seen this happen again and
again where the product is tested in the Far East and passes, but when it
comes back to the USA for QA sampling it fails simply due to this problem.
A lot of times the product is simply shipped to distributors for sale and
when the final customer gets it and tests it for incoming QC the whole lot
is returned to the manufacturer as defective. Of course the manufacturer
blames the test equipment maker but in most cases I had found that the
product had indeed changed over a period of time and did not meet specs.
When left under power for a while it would return to it's original specs.
Bill
----- Original Message -----
From: "Frank Stellmach" frank.stellmach@freenet.de
To: volt-nuts@febo.com
Sent: Saturday, January 18, 2014 8:41 AM
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
volt-nuts mailing list -- volt-nuts@febo.com
To unsubscribe, go to
https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts
and follow the instructions there.
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@hotmail.com
To: "Discussion of precise voltage measurement" volt-nuts@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@freenet.de
To: volt-nuts@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
volt-nuts mailing list -- volt-nuts@febo.com
To unsubscribe, go to
and follow the instructions there.
volt-nuts mailing list -- volt-nuts@febo.com
To unsubscribe, go to
https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts
and follow the instructions there.
Can you imagine what it would cost to get that calibrated?
Tom
----- Original Message -----
From: "Bill Gold" wpgold3637@att.net
To: "Discussion of precise voltage measurement" volt-nuts@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@hotmail.com
To: "Discussion of precise voltage measurement" volt-nuts@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@freenet.de
To: volt-nuts@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
volt-nuts mailing list -- volt-nuts@febo.com
To unsubscribe, go to
and follow the instructions there.
volt-nuts mailing list -- volt-nuts@febo.com
To unsubscribe, go to
https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts
and follow the instructions there.
volt-nuts mailing list -- volt-nuts@febo.com
To unsubscribe, go to
https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts
and follow the instructions there.
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@att.net
To: "Discussion of precise voltage measurement" volt-nuts@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@hotmail.com
To: "Discussion of precise voltage measurement" volt-nuts@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@freenet.de
To: volt-nuts@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
Of course you would need to calibrate a JJ standard. If you recall,
the JJ works by being cooled to some LN2 like temperature, and then
being fed with a microwave frequency that is part of the standard's
definition. If the temperature is wrong, or the frequency is wrong,
or ..., the voltage will be wrong. The whole point behind the JJ is
that it connects the standard voltage to the standard frequency/time
... the most accurately specified of the known standards.
Cs standards, even though they are primary standards, are also in need
of calibration because the frequency they create is dependent on the
magnetic field surrounding the tube, and the construction of the tube.
All Josephson Junction V standards produce a slightly different voltage,
and all Cs standards produce a slightly different frequency.
-Chuck Harris
Joe Hobart wrote:
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
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@npgcable.com
To: tmiller11147@verizon.net; volt-nuts@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@att.net
To: "Discussion of precise voltage measurement" volt-nuts@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@hotmail.com
To: "Discussion of precise voltage measurement" volt-nuts@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@freenet.de
To: volt-nuts@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
volt-nuts mailing list -- volt-nuts@febo.com
To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts
and follow the instructions there.
In message 52DB4299.2080209@erols.com, Chuck Harris writes:
Of course you would need to calibrate a JJ standard. If you recall,
the JJ works by being cooled to some LN2 like temperature, and then
being fed with a microwave frequency that is part of the standard's
definition. If the temperature is wrong, or the frequency is wrong,
Actually that's not really true.
The temperature has no effect on the output, as long as it is low
enough to ensure superconductivity, and if it isn't, you get no
output.
The frequency has to be right, and since it is typically way up
in microwave territory, 75 GHz or thereabout, that is somewhat
finicky stuff.
It's not quite the plug&play of a HP5071A, but it isn't that far
from it.
--
Poul-Henning Kamp | UNIX since Zilog Zeus 3.20
phk@FreeBSD.ORG | TCP/IP since RFC 956
FreeBSD committer | BSD since 4.3-tahoe
Never attribute to malice what can adequately be explained by incompetence.
Joe:
I would guess that a local JJ would have to be compared with a
"standard" JJ. Since NIST says "Ours is correct and yours could be a little
more or less than ours, you need to know the difference". But this all get
into a really "gray" area in the 0.01 ppm region. So what are you going to
do? Move your JJ to NIST? Not practical! My suggestion about a JJ in a
9.5 digit was just to get a more stable voltage reference. Of course at the
present time given the fact that the JJ has to be cooled to below 4.2 K
makes this idea more than a little impractical. Of course you could setup
to reference the voltmeter to a stand alone JJ in your workshop. See this
website for a turnkey unit you can get. www.supracon.com They have two
models, one which uses liquid He and the other has a Cryocooler. I am sure
that you can talk the little lady into this as a birthday present?
I am not sure what Fluke does to be "traceable" to NIST but I would
imagine that Fluke regularly sends carefully characterized 734A units to
NIST in a round robin so that they can accomplish this. There is an
application note somewhere that talks about this.
Same with the Hz, the ohm and so on, you have to somehow reference it to
NIST, to claim you are "traceable to NIST".
Bill
----- Original Message -----
From: "Joe Hobart" nova@npgcable.com
To: "Tom Miller" tmiller11147@verizon.net; "Discussion of precise voltage
measurement" volt-nuts@febo.com
Sent: Saturday, January 18, 2014 4:44 PM
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@att.net
To: "Discussion of precise voltage measurement" volt-nuts@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@hotmail.com
To: "Discussion of precise voltage measurement" volt-nuts@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@freenet.de
To: volt-nuts@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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