Author Topic: Ultra Low Noise Reference 2DW232, 2DW233, 2DW23x  (Read 134487 times)

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Offline orin

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Re: Ultra Low Noise Reference 2DW232, 2DW233, 2DW23x
« Reply #50 on: October 23, 2016, 07:39:21 pm »
Count me in for 20 in the USA.
 

Offline branadic

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Re: Ultra Low Noise Reference 2DW232, 2DW233, 2DW23x
« Reply #51 on: October 23, 2016, 08:38:08 pm »
I'm interested in 30 pieces too. Germany/Europe
Fluke 8050A | Prema 5000 | Prema 5017 SC | Advantest R6581D | GenRad 1434-G | Datron 4000A | Tek 2465A | VNWA2.x with TCXO upgrade and access to: Keysight 3458A, Keithley 2002, Prema 5017 SC, 34401A, 34410A, Keithley 2182A, HDO6054, Keysight 53230A and other goodies at work
 

Offline hammy

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Re: Ultra Low Noise Reference 2DW232, 2DW233, 2DW23x
« Reply #52 on: October 23, 2016, 08:48:06 pm »
I would also be interested for 30 pcs for the EU/Germany group buy.

Thank you!  :-+
 

Offline Nuno_pt

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Re: Ultra Low Noise Reference 2DW232, 2DW233, 2DW23x
« Reply #53 on: October 23, 2016, 09:22:25 pm »
The price from the link that @zlymex post from tabao shows $0.24 each, plus shipping from @zlymex to both US & EU host's.
The shipping from @zlymex to each host (1 in US, 1 in EU) would be divided by all in each group.
Then each one in that group (US & EU) would pay the shipping from the host to is address to the host.
Also from my point of view makes more sense after @zlymex give the shipping price for each host, and we've close the numbers of the buy, that all should pay directly to @zlymex, leaving that way only the last shipment to pay to the host.

From what I get till now, here are some numbers;

Europe:
@Theboel - 20
@eliocor - 30 (Buy Limit)
@pmcouto - 30 (Buy Limit)
@Squantor - 30 (Buy Limit)
@pelule - 30
@branadic - 30
@hammy - 30
@ Nuno_pt - 30
@Cerebus - 20
@manganin - 30 (Buy Limit)
@2N3055 - 20
@MosherIV - 3
@janode - 20
@Alex Nikitin - 30 (Buy Limit)
@babysitter - 30
@plesa - 30



US:
@evb149 - 30 (Buy Limit)
@MatteoX - 30 (Buy Limit)
@orin - 20
@VintageNut - 25
@Galaxyrise - 20

Asia - 20


Anyone missing?

Updated & Buy Limit impose to 30 for person, because of the explanation below given by @zlymex, after this there could be organize another group buy for those that need more parts, but this propose is to try the 2DW23x series for drift beside the LM399/LTZ1k.

Updated
« Last Edit: October 25, 2016, 07:38:57 am by Nuno_pt »
Nuno
CT2IRY
 

Offline Cerebus

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Re: Ultra Low Noise Reference 2DW232, 2DW233, 2DW23x
« Reply #54 on: October 23, 2016, 09:48:45 pm »
Put me down for 20 or whatever turns out to be the nearest convenient quantity.
Anybody got a syringe I can use to squeeze the magic smoke back into this?
 

Offline manganin

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Re: Ultra Low Noise Reference 2DW232, 2DW233, 2DW23x
« Reply #55 on: October 23, 2016, 09:51:42 pm »
200 pcs / EU
 

Online 2N3055

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Re: Ultra Low Noise Reference 2DW232, 2DW233, 2DW23x
« Reply #56 on: October 23, 2016, 10:19:45 pm »
Can I have 20 pcs/EU please?
 

Offline martinr33

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Re: Ultra Low Noise Reference 2DW232, 2DW233, 2DW23x
« Reply #57 on: October 23, 2016, 10:54:04 pm »
Mine came from here:

https://world.taobao.com/item/35862405041.htm?fromSite=main

I think that is the same supplier. The ones I have have a colored dot on the side, and a black diamond logo, part number and date code on the top. One batch is 2016, the others are 2015.

I opened a couple up, they have a white silicone seal not an epoxy seal. I'll try to get the silicone off, get some pictures.
 

Offline zlymex

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Re: Ultra Low Noise Reference 2DW232, 2DW233, 2DW23x
« Reply #58 on: October 23, 2016, 11:36:49 pm »
Well, that amount(summarized by Nuno_pt) certainly exceed my expectation.
Like I said, I'll buy 200-300 pcs and ship to one oversea location(USA) at my own expense.
The purpose of the 'group buy' from my point of view is for test for EEVBLOG members, therefore I hope not exceed 20-30 pcs each.
The reason for the limit is the availability from one seller, also because of the customs here which may have very strict rule for random packages.
Again, This zener has the best noise property I've ever tested, but the T.C. is just average, and drift is a question mark.
 

Online blueskull

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Re: Ultra Low Noise Reference 2DW232, 2DW233, 2DW23x
« Reply #59 on: October 23, 2016, 11:41:16 pm »
also because of the customs here which may have very strict rule for random packages.

I think customs only cares about incoming packages, not outgoing packages.
 

Offline zlymex

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Re: Ultra Low Noise Reference 2DW232, 2DW233, 2DW23x
« Reply #60 on: October 24, 2016, 12:01:50 am »
The price from the link that @zlymex post from tabao shows $0.24 each, plus shipping from @zlymex to both US & EU host's.
The shipping from @zlymex to each host (1 in US, 1 in EU) would be divided by all in each group.
Then each one in that group (US & EU) would pay the shipping from the host to is address to the host.
Also from my point of view makes more sense after @zlymex give the shipping price for each host, and we've close the numbers of the buy, that all should pay directly to @zlymex, leaving that way only the last shipment to pay to the host.

From what I get till now, here are some numbers;

Europe:
@Theboel - 20
@eliocor - 30 to 50
@pmcouto - 50
@Squantor - 20 or more
@pelule - 30
@branadic - 30
@hammy - 30
@ Nuno_pt - 30
@Cerebus - 20
@manganin - 200


US:
evb149 - 25 to 250
MatteoX - 25 or more
orin - 20


Anyone missing?
Thanks very much for the plan and summery. One reason(the expense on me) is that I have difficulty in receiving money from where I reside.
There is no worry thought for this zener to sold out even the group test results are positive because the zener is in production.
The there one slight worry though, the quality may vary among batches. The taobao link I posted is the one which I've tested and proofed to have low noise.

The reason I bought 550pcs of 2DW234 from another seller is because one of my friends bought some samples before and tested to have narrow distribution of zero TC current. The seller got 1100 pcs and we bought them all. These 2DW234 were dated 13-2(Feb 2013) and we cannot find any others seller selling the same thing. New devices, although low in noise, they tends to have large(but similar) distribution of zero TC current, regardless of the part number.
 

Online blueskull

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Re: Ultra Low Noise Reference 2DW232, 2DW233, 2DW23x
« Reply #61 on: October 24, 2016, 12:07:25 am »
One reason(the expense on me) is that I have difficulty in receiving money from where I reside.

Or they can pay me to my PayPal or WellsFargo account, then I can transfer money to you in CNY from my SPDB account.
I live in US and I have both US and Chinese bank accounts.
 

Offline Cerebus

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Re: Ultra Low Noise Reference 2DW232, 2DW233, 2DW23x
« Reply #62 on: October 24, 2016, 12:54:43 am »
also because of the customs here which may have very strict rule for random packages.

I think customs only cares about incoming packages, not outgoing packages.

Not Chinese customs. They clear outbound packages too. When I order things from China that come with tracking codes I often explicitly see the step in the tracking details. For example, from an order that's currently in transit:

09-Oct-2016 09:41   Departure export customs   SHENZHEN

For the most part they seem to go into export customs and come straight out again, but I've had orders that have sat in Chinese export customs for several days.
Anybody got a syringe I can use to squeeze the magic smoke back into this?
 

Offline Cerebus

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Re: Ultra Low Noise Reference 2DW232, 2DW233, 2DW23x
« Reply #63 on: October 24, 2016, 12:56:57 am »
One reason(the expense on me) is that I have difficulty in receiving money from where I reside.

Or they can pay me to my PayPal or WellsFargo account, then I can transfer money to you in CNY from my SPDB account.
I live in US and I have both US and Chinese bank accounts.

This is how people end up in 'extended screening' at the air port. The NSA connect you to a series of payments that take a circuitous route via a Chinese bank account...  ;)
Anybody got a syringe I can use to squeeze the magic smoke back into this?
 

Online blueskull

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Re: Ultra Low Noise Reference 2DW232, 2DW233, 2DW23x
« Reply #64 on: October 24, 2016, 12:57:49 am »
Not Chinese customs. They clear outbound packages too. When I order things from China that come with tracking codes I often explicitly see the step in the tracking details. For example, from an order that's currently in transit:

09-Oct-2016 09:41   Departure export customs   SHENZHEN

For the most part they seem to go into export customs and come straight out again, but I've had orders that have sat in Chinese export customs for several days.

I meant Chinese customs does not seize or check outgoing packages, but of course, a package will have to go through customs before entering or leaving China.
 

Offline evb149

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Re: Ultra Low Noise Reference 2DW232, 2DW233, 2DW23x
« Reply #65 on: October 24, 2016, 01:04:12 am »
Thanks zlymex, I appreciate all the information you have shared on your noise reference experiments and noise tester circuit. 

I did not intend to ask for too many pieces for convenience of a group buy.  I had just assumed that after seeing your talks of ordering 550 and hundreds more that those were usual lot quantities and perhaps also were less expensive in such quantities as well.

I think some number from a few up to 30 is good for testing for me as you've suggested. 
I was interested in Nuno_pt's idea to use more than 14 in series to achieve a 100V low noise reference, or the idea others have mentioned to use several in parallel to reduce random noise by square root (number) or similar ideas so I thought I could eventually use more than 100 if they worked at least reasonably well.  But I have no urgent short term need to do more than testing with less quantities.

A particular concern to me about finding that a small number of these are good (low noise even if drift is more than TI/Analog/Linear/Maxim similar high grade references) is that it may be hard to order the Shanghai 17th Radio Factory's "good model" part since mostly resellers seem to sell the "junk" versions even accompanied with pictures and specifications of the "good model" part.  So there is temptation to "get the right one while it is clear how to do so".

Another concern is to find that there is some quality of a particular batch of them that is good and not being able to find similar units in the future or from different suppliers so therefore the characterization work could be much harder if trying to characterize different batches ordered over time vs. one batch that may be more consistent.  Though I see that you say that it is not your recent experience that the recently available batches are very consistent in parametric spreads anyway.  But at least we know that the model is good if not the characteristics as tight as the best 2013 batch you found.

And of course that it is hard (so I have seen from others comments, this would be my first try if I should attempt it for this) and maybe expensive depending on the seller's desire to ship internationally in some way to buy from Taobao directly and get the items shipped to the USA for a non-Chinese speaking customer.  But I saw another comment from a different thread that maybe it is easier than it once was to order internationally from Taobao.  If it is not so hard / costly then I and I suppose others would not mind to just order individually if wanting more quantities.
I will see what I can learn about using Taobao.  If the "e packet" low cost shipping service is available easily for US customers and there are no significant other problems/costs for ordering/shipping per order then maybe USA customers could order without causing inconvenience to you.
https://www.eevblog.com/forum/chat/why-use-taobao/msg953114/#msg953114
https://www.eevblog.com/forum/chat/why-use-taobao/msg953118/#msg953118
 
I guess that it is not known that the Shanghai 17th Radio Factory sells these parts "directly" through Taobao / similar markets in low (hundreds) quantities directly to consumers if this particular Taobao seller might not be expected to have such quantities of stock and perhaps could even eventually substitute other factories / models of parts if they run out of this batch?  It seems like they might do some good business with US and European customers if they somehow sold easily via paypal / ebay / whatever.  My own interest is as an aspiring novice volt-nutter but I'd guess it'd be popular for audio enthusiasts and such.

I also noticed that some people (who I have never done any business with so I just mention the messages I have seen in searching for keyword taobao here for my own education about buying from it) say they routinely export items from China to sell through eBay so if demand exceeds what is convenient to arrange for a small group buy I guess someone who routinely sells through ebay might agree to carry this part in their ebay store if they can source the "good version" from the Shanghai 17th Radio Factory or other acceptably certain reseller.  Franky, Tayda, maybe even someplace like Adafruit, Sparkfun, or similar might source / sell such a thing.
https://www.eevblog.com/forum/chat/what-site-to-use-for-puchasing-china-stuff-at-eu/msg176762/#msg176762
 

Offline VintageNut

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Re: Ultra Low Noise Reference 2DW232, 2DW233, 2DW23x
« Reply #66 on: October 24, 2016, 01:08:01 am »
The price from the link that @zlymex post from tabao shows $0.24 each, plus shipping from @zlymex to both US & EU host's.
The shipping from @zlymex to each host (1 in US, 1 in EU) would be divided by all in each group.
Then each one in that group (US & EU) would pay the shipping from the host to is address to the host.
Also from my point of view makes more sense after @zlymex give the shipping price for each host, and we've close the numbers of the buy, that all should pay directly to @zlymex, leaving that way only the last shipment to pay to the host.

From what I get till now, here are some numbers;

Europe:
@Theboel - 20
@eliocor - 30 to 50
@pmcouto - 50
@Squantor - 20 or more
@pelule - 30
@branadic - 30
@hammy - 30
@ Nuno_pt - 30
@Cerebus - 20
@manganin - 200


US:
evb149 - 25 to 250
MatteoX - 25 or more
orin - 20


Anyone missing?


25 pcs for me. If Zlymex ships to me, I will ship to the other people in the US. I can also ship USPS to Indonesia. I have Paypal and I can receive the shipping fees. I have participated in sharing components on Diyaudio.com  These parts will go fast.

If Zlymex can only get 300 pcs, there will not be an ability to send 200 pcs to anyone. Everybody be realistic about how many of these parts are available.

The idea is for people to try these Zeners to see if they are lower noise and can work as a reference for DIY metrology at home.

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Online blueskull

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Re: Ultra Low Noise Reference 2DW232, 2DW233, 2DW23x
« Reply #67 on: October 24, 2016, 01:12:46 am »
This is how people end up in 'extended screening' at the air port. The NSA connect you to a series of payments that take a circuitous route via a Chinese bank account...  ;)

I have my PhD work in a sensitive field, high density power packaging, which is ITAR controlled, and I receive funding from USDOE plus my lab has connection with USDOD/LMCO. Needless to say, I should have already been tagged.
 

Offline MosherIV

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Re: Ultra Low Noise Reference 2DW232, 2DW233, 2DW23x
« Reply #68 on: October 24, 2016, 06:52:24 am »
Hi

Can I have 2 or 3 peices please?

Thanks
 

Offline zlymex

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Re: Ultra Low Noise Reference 2DW232, 2DW233, 2DW23x
« Reply #69 on: October 24, 2016, 07:15:51 am »
Thank everyone for the info/suggestions/comments.

Initially in this post, I just share some information, providing aliexpress.com(same boss as taobo) links, because I know many people buy electric parts there even with free shipment. Then I heard some bad news that they didn't ship or wrong parts, plus Nuno_pt suggest me to help, that's when I came in.

I've just asked our company's postal office that there is only one postal company to mail to USA, which is EMS China, although the price is high(240 RMB for 500g), I can cope with that. I've never heard ePacket, may be I've never mail anything abroad, may be that service is not available to my area, may be I didn't ask other places.

I'm buying 2DW232 from taobao now, the data code is 15-4, for which I've bought and tested before.

If everything is Ok(my spot check, postal, tests by recipients), and anyone need large quantity, a real group buy can be start later. But if that is still by me/taobao, I will again buy small samples first.

Again, this is a trial at my expense, I don't have any connections with the seller at taobao or the 17th radio factory. If anyone need some piece of 2DW232 for test, leave your comments here, my intention is to get more people involved in testing. For those who have said needing more than 30 pcs, lets see if there are something left.
« Last Edit: October 24, 2016, 07:25:46 am by zlymex »
 
The following users thanked this post: hammy, Nuno_pt, Squantor

Online blueskull

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Re: Ultra Low Noise Reference 2DW232, 2DW233, 2DW23x
« Reply #70 on: October 24, 2016, 07:23:00 am »
I've never heard ePacket, may be I've never mail anything abroad, may be that service is not available to my area, may be I didn't ask other places.

ePacket is China Post's special service only offered to professional exporters. For instance, if you constantly ship abroad with an export license, you can get an ePacket account.
 

Offline Nuno_pt

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Re: Ultra Low Noise Reference 2DW232, 2DW233, 2DW23x
« Reply #71 on: October 24, 2016, 10:11:53 am »
Post with quantities updated above, because of this Zener is still in production and can be bought in another group buy with the help from @zlymex, and also because of what @zlymex explain above, the limit will 30 pieces for each person, at a later stage another group buy can be organize and the ones that want more can buy on the second round.

This small quantities of 30 is to choose the best's and to make some PCB's, and look at the comparison about drift in relation to the more use Zeners like LM399/LTZ1k, and see if they can be use also for references in a home lab.

240RMB is 33€ at today exchange, for the EU group with the current committed members the shipping cost from @zlymex to the EU host is 33€/11 members = 3€ each members + ~0.24€ each Zener + shipping from the EU host to each one.

So for 30 pieces that will be 0.24€ each x 30 pieces = 7.20€ + 3€ shipping from @zlymex to EU = 10.20€, plus the shipping from the host to each.
Nuno
CT2IRY
 

Offline manganin

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Re: Ultra Low Noise Reference 2DW232, 2DW233, 2DW23x
« Reply #72 on: October 24, 2016, 10:20:28 am »
200 pcs / EU

My new 100 input scanner will be ready soon. Or actually two of them.

The seller's price at Taobao looks like USD $0.25 each

Cheap enough for a statistical experiment. If available in large quantity...
 

Offline Alex Nikitin

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Re: Ultra Low Noise Reference 2DW232, 2DW233, 2DW23x
« Reply #73 on: October 24, 2016, 10:48:34 am »
Count me in for 50 pieces.

Cheers

Alex
 

Offline janode

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Re: Ultra Low Noise Reference 2DW232, 2DW233, 2DW23x
« Reply #74 on: October 24, 2016, 03:42:43 pm »
 


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