Author Topic: Ultra Precision Reference LTZ1000  (Read 958923 times)

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Offline MegaVolt

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Re: Ultra Precision Reference LTZ1000
« Reply #2300 on: May 23, 2018, 01:32:13 pm »
measuring with the parallel resistor a few seconds later.
I was not attentive :( It was about jumping relative measurements in a short time.

Thank you corrected.
 

Offline keen101

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Re: Ultra Precision Reference LTZ1000
« Reply #2301 on: June 19, 2018, 06:27:46 am »
So, i know this is many years too late,  and maybe there is zero Interest in this anymore, but there were many people who had wanted an LTZ1000 board way back when i posted my HP/Agilent Clone on my blog several years back (wordpress.com/2013/02/12/hpagilent-03458-66509-7v-dc-reference-clone/).

Since so many had asked me for one,  i finally made a few boards and put them on ebay. It seems no one wants one anymore,  so maybe it was a waste of time, and if so, oh well, still a neat little board I'm proud of.

Here is the ebay link if anyone is interested.  Thanks. (https://rover.ebay.com/rover/0/0/0?mpre=https%3A%2F%2Fwww.ebay.com%2Fulk%2Fitm%2F113011267007).
 

Offline TheSteve

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Re: Ultra Precision Reference LTZ1000
« Reply #2302 on: June 19, 2018, 06:51:56 am »
I think the problem may be that your price is a little bit too high. You can buy original 3458A A9 ref boards for less quite often on ebay and they use the LTZ1000ACH.
VE7FM
 

Offline Dr. Frank

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Re: Ultra Precision Reference LTZ1000
« Reply #2303 on: June 19, 2018, 08:16:09 am »
Nice board, but the price is way too high.
Also, it's lacking some information, like oven temperature set point.. is it still 95°C (15k/1k divider), or did you adapt it to the non-A version (at least 10°C less), and for metrology application, i.e. smallest possible expected drift, like 13k/1k and 65°C?

Frank

PS: And the module should have been trimmed for lowest T.C.
« Last Edit: June 19, 2018, 09:35:42 am by Dr. Frank »
 
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Offline Echo88

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Re: Ultra Precision Reference LTZ1000
« Reply #2304 on: June 19, 2018, 08:39:21 am »
About 130€ BOM and you want 350$. Price is way to high and would only be okay if it would already have a long-term-burn-in and calibration data so one can use it directly in a used 3458A for example.
 

Offline TiN

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Re: Ultra Precision Reference LTZ1000
« Reply #2305 on: June 19, 2018, 08:50:15 am »
Based on eBay listing photos, sadly 15K/1K is used with CH chip.
YouTube | Metrology IRC Chat room | Live-cam | Share T&M documentation? Upload! No MB limit, firmwares, photos.
 
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Offline Cerebus

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Re: Ultra Precision Reference LTZ1000
« Reply #2306 on: June 19, 2018, 11:51:55 am »
I think the problem may be that your price is a little bit too high. You can buy original 3458A A9 ref boards for less quite often on ebay and they use the LTZ1000ACH.

Also on a $350 ticket item a description that includes a phrase like "The chip has been tested and appears to be working correctly in circuit, but has not been burned in for even better stability." doesn't exactly inspire confidence. Someone who's going to fork out $350 wants a guarantee that the board is working and meets specifications, which for an item like the A9 board includes a drift test over at least several months. That is the value add and that is what justifies a price that is significantly above the BOM cost.
Anybody got a syringe I can use to squeeze the magic smoke back into this?
 
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Offline doktor pyta

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Re: Ultra Precision Reference LTZ1000
« Reply #2307 on: June 19, 2018, 02:34:22 pm »
From ebay item's description:

'LTZ1000 heat compensated chip standard (which often goes bad)'

prove it

Offline Kleinstein

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Re: Ultra Precision Reference LTZ1000
« Reply #2308 on: June 19, 2018, 05:04:50 pm »
I would not expect a lot of failing LTZ ref modules in the 3458. They are supposed to be well tested and burned in. So the bad ones with excessive drift or significant popcorn noise (which might often come together) should be sorted out. There still seem to be rare cases with HP refs. to show popcorn noise, but I am afraid the chances are higher with the untested replacement boards.
 

Offline martinr33

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Re: Ultra Precision Reference LTZ1000
« Reply #2309 on: June 19, 2018, 05:52:08 pm »
I think that there would be some interest in the bare board from this group. That might be a way to recover your investment. You might also find some buyers for the completed board, at a price that lets you recover the parts cost.

Thanks for doing this, I know that it isn't meeting your expectations but it is nice to have this piece of engineering done. 
 

Offline VK5RC

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Re: Ultra Precision Reference LTZ1000
« Reply #2310 on: July 02, 2018, 08:05:44 am »
If I recall correctly - somewhere in this post - somebody gave mentioned a good quality socket that could be used to temporarily fit an LTZ - to try and sort some 'good ones' without a full board each.
Does any one recall the detail of the socket/source etc or did I imagine it?  :-//
Whoah! Watch where that landed we might need it later.
 

Offline SvanGool

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Re: Ultra Precision Reference LTZ1000
« Reply #2311 on: July 02, 2018, 09:07:07 am »
# Don't hurry, the past will wait. #
 

Offline VK5RC

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Re: Ultra Precision Reference LTZ1000
« Reply #2312 on: July 02, 2018, 09:55:29 am »
Whoah! Watch where that landed we might need it later.
 

Offline branadic

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Re: Ultra Precision Reference LTZ1000
« Reply #2313 on: September 16, 2018, 12:33:44 pm »
Since I received a few vintage LTZ1000 samples from lowimpedance and need some boards for comparison I decided to use the design of Dr. Frank. I modified his design to fit into a Hammond 1455C1201 case and added LT1763 (SO8) voltage regulator, giving 12V. This is how it currently looks like. The 3 blocks to the right indicate the place for Pomona 3770 binding posts.

-branadic-
Metrology Meeting 2020 is canceled. Looking forward for MM2021
 
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Offline Haasje93

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Re: Ultra Precision Reference LTZ1000
« Reply #2314 on: September 18, 2018, 10:31:26 am »
It looks really nice! :-+
 

Offline Dr. Frank

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Re: Ultra Precision Reference LTZ1000
« Reply #2315 on: September 18, 2018, 12:18:52 pm »
Hello,
the loose power supply GND cable must NOT be connected to the negative reference star point, but instead to the jack farther right.
I'd recommend to separate the power supply thermally and shileding-wise.

I see no basic deviation to my LTZ design, so far, so the rest is ok.

Frank
 
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Offline Andreas

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Re: Ultra Precision Reference LTZ1000
« Reply #2316 on: September 18, 2018, 04:38:48 pm »
+1 for the thermal isolation between LT1763 and LTZ.
(thats why I will do a re-design of my B-revision)
In your case it might be less urgent if you have a stabilized external supply instead of battery.

with best regards

Andreas
 

Offline branadic

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Re: Ultra Precision Reference LTZ1000
« Reply #2317 on: September 18, 2018, 07:37:50 pm »
Thanks for the feedback. Changed the loose wire to JP2, added a thermal slot between regulator and reference ciruit and changed two MKS 100nF to MKP2 100nF. Attached the almost final state of the board.

-branadic-
« Last Edit: September 19, 2018, 07:07:15 pm by branadic »
Metrology Meeting 2020 is canceled. Looking forward for MM2021
 

Offline branadic

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Re: Ultra Precision Reference LTZ1000
« Reply #2318 on: September 19, 2018, 06:01:10 pm »
I will order some boards within the next days. Someone out there who wants a few boards of this layout as well?

-branadic-
Metrology Meeting 2020 is canceled. Looking forward for MM2021
 

Offline BradC

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Re: Ultra Precision Reference LTZ1000
« Reply #2319 on: September 19, 2018, 11:39:06 pm »
I will order some boards within the next days. Someone out there who wants a few boards of this layout as well?

-branadic-

I'll put my hand up for one please.
 

Offline GregDunn

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Re: Ultra Precision Reference LTZ1000
« Reply #2320 on: September 20, 2018, 12:57:51 am »
Are you selling boards only, or boards with the LTZ1000?
 

Offline branadic

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Re: Ultra Precision Reference LTZ1000
« Reply #2321 on: September 20, 2018, 05:57:16 am »
Boards only...
For orders please write me a short pm with how many boards you need. I will close this offering by the end of next week and order the boards in the necessary quantities.

-branadic-
Metrology Meeting 2020 is canceled. Looking forward for MM2021
 
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Offline branadic

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Re: Ultra Precision Reference LTZ1000
« Reply #2322 on: September 20, 2018, 04:53:04 pm »
Wow, didn't expect such a response. I think I will order at Elecrow and pcb cost will be in the order of $2 per board or less depending on the final quantity plus shipping cost (Airmail) plus shipping to you guys (simple envelope to keep cost down). Thus I changed the outer form to a rectangle of size 120 x 50mm². PCB color will be black with immersion gold, single layer board.
Attached is the final schematic.
Please send me an official email adress with the PN too. Thanks.

-branadic-
« Last Edit: September 20, 2018, 05:13:31 pm by branadic »
Metrology Meeting 2020 is canceled. Looking forward for MM2021
 
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Offline Kleinstein

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Re: Ultra Precision Reference LTZ1000
« Reply #2323 on: September 20, 2018, 05:18:31 pm »
The pot for gain adjustment in the final stage is a little odd. Normally one avoids using such low ohms pots, as the wiper contact may not be that reliable.  The more normal way is to have something like 10-100 Ohms in parallel to a 10 K pot with 5-100 K in series.
 

Offline branadic

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Re: Ultra Precision Reference LTZ1000
« Reply #2324 on: September 20, 2018, 05:51:24 pm »
Since this board is working for Frank and since I had the chance to measure one of his reference boards I wouldn't complain ;)

-branadic-
Metrology Meeting 2020 is canceled. Looking forward for MM2021
 


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