I have struck a deal with Shanghai 17th Radio Factory, who makes those ultra-low-noise 2DW23x Zener diodes. I can source those parts directly from the factory at 75 US cents each, and each order up to about 1500-2000 pieces will cost 5 US dollars to post through air mail. The factory also set a minimum aggregated order amount of 100 before they would waiver the $5 handling fee.
I am starting this thread so you guys can match and aggregate orders before I submit it to the factory. If you have posted an order here please also send a PM to notify me. I will send you a PM as well as update this thread to reflect the current aggregated order number, and if it managed to reach 100 at noon Beijing Time every Tuesday I will place an order to the factory.
Sent order list: (Total: 1915)
Type | Name | Qty | Country | Flags |
2DW232 | Assaf | 10 | Israel | PSD |
2DW233 | Assaf | 10 | Israel | PSD |
2DW233 | Lukier | 20 | United Kingdom | PSD |
2DW233 | mmagin | 10 | USA | PSD |
2DW233 | Harfner | 20 | Germany | PSD |
2DW233 | douardda | 40 | France | PSD |
2DW233 | enut11 | 20 | Australia | PSD |
2DW232 | bertik | 10 | France | PSD |
2DW233 | bertik | 10 | France | PSD |
2DW234 | bertik | 10 | France | PSD |
2DW232 | nadona | 25 | USA | PSD |
2DW233 | nadona | 25 | USA | PSD |
2DW233 | pmcouto | 20 | Portugal | PSD |
2DW232 | julian1 | 10 | Australia | PSD |
2DW233 | julian1 | 10 | Australia | PSD |
2DW234 | julian1 | 10 | Australia | PSD |
2DW235 | julian1 | 10 | Australia | PSD |
2DW236 | julian1 | 10 | Australia | PSD |
2DW232 | rastro | 10 | USA | PSD |
2DW233 | rastro | 10 | USA | PSD |
2DW232 | svangool | 20 | Netherlands | PSD |
2DW232 | mimmus78 | 10 | Italy | PSD |
2DW233 | mimmus78 | 10 | Italy | PSD |
2DW232 | rachaelp | 10 | UK | PSD |
2DW233 | rachaelp | 10 | UK | PSD |
2DW232 | elecdonia | 10 | USA | PSD |
2DW233 | elecdonia | 10 | USA | PSD |
2DW232 | technogeeky | 10 | USA | PSD |
2DW233 | technogeeky | 10 | USA | PSD |
2DW232 | RandallMcRee | 20 | USA | PSD |
2DW232 | peter.mitchell | 100 | Australia | PSD |
2DW232 | CaféNoir | 50 | France | PSD |
2DW233 | CaféNoir | 30 | France | PSD |
2DW232 | iainwhite | 10 | USA | PSD |
2DW233 | iainwhite | 10 | USA | PSD |
2DW232 | picburner | 20 | Italy | PSD |
2DW232 | chickenHeadKnob | 25 | | PSD |
2DW232 | cellularmitosis | 20 | USA | PSD |
2DW235 | IconicPCB | 25 | Australia | PSD |
2DW236 | IconicPCB | 25 | Australia | PSD |
2DW232 | vindoline | 15 | USA | PSD |
2DW233 | vindoline | 15 | USA | PSD |
2DW234 | chuckb | 600 | USA | PSD |
2DW235 | chuckb | 100 | USA | PSD |
2DW232 | Muxr | 100 | USA | PSD |
2DW232 | uwezi | 10 | Sweden | PSD |
2DW233 | uwezi | 20 | Sweden | PSD |
2DW234 | uwezi | 10 | Sweden | PSD |
2DW232 | alm | 15 | The Netherlands | PSD |
2DW233 | alm | 15 | The Netherlands | PSD |
2DW232 | Vojtech | 15 | Czech | PSD |
2DW233 | Vojtech | 15 | Czech | PSD |
2DW232 | Rycroft | 10 | Australia | PSD |
2DW233 | Rycroft | 10 | Australia | PSD |
2DW232 | maerki | 10 | Switzerland | PSD |
2DW233 | maerki | 10 | Switzerland | PSD |
2DW234 | maerki | 10 | Switzerland | PSD |
2DW232 | BU508A | 10 | Germany | PSD |
2DW233 | BU508A | 10 | Germany | PSD |
2DW234 | BU508A | 10 | Germany | PSD |
2DW232 | SZA263 | 20 | Italy | PSD |
2DW233 | SZA263 | 20 | Italy | PSD |
2DW232 | welterde | 10 | Germany | PSD |
2DW233 | welterde | 10 | Germany | PSD |
2DW234 | welterde | 10 | Germany | PSD |
2DW232 | floobydust | 10 | Canada | PSD |
2DW232 | Dave | 50 | Slovenia | PSD |
2DW232 | texaspyro | 20 | USA | PSD |
2DW233 | texaspyro | 20 | USA | PSD |
Processing Order List: (0/100)
Outstanding Order List: (70/100)
Type | Name | Qty | Country | Flags |
2DW232 | Octane | 20 | USA | |
2DW233 | Octane | 10 | USA | |
2DW234 | Octane | 10 | USA | |
2DW232 | cellularmitosis | 10 | USA | |
2DW233 | cellularmitosis | 10 | USA | |
2DW234 | cellularmitosis | 10 | USA | |
I am now accepting both PayPal and bank T/T as methods of payment. T/T will be preferred for orders equal to or more than 100 pieces in one go. If you wish to pay via T/T, please make sure you can work with OpenPGP-encrypted Email traffic, as I do not want to send my banking details unprotected.
You can sign me up for 10-20. Thx, Assaf
PS - if you prefer this in the form of a list - here it is - please copy below and add the quantity you are interested in:
Name Qty Country
Assaf 20 Israel
You can sign me up for 10-20. Thx, Assaf
PS - if you prefer this in the form of a list - here it is - please copy below and add the quantity you are interested in:
Name Qty Country
Assaf 20 Israel
Please specify the part number.
Please sign me up for 20 as well.
Type | Name | Qty | Country |
TBD | Assaf | 20 | Israel |
2DW233 | Lukier | 20 | United Kingdom |
Type Name Qty Country
2DW233 Assaf 20 Israel
2DW233 Lukier 20 United Kingdom
2DW233 mmagin 10 USA
2DW233 Harfner 20 Germany
(As already sent by PM)
Hello,
thanks for offering this opportunity again!
Would you also offer the 2DW232 as well?
It seems to have considerably less noise according to my measurements -
though this may be batch dependent.
Thanks,
Bertik
Hello Technix - can you post datasheet of 2DW232 and 2DW233 buried zeners ?
Can you specify website of Shanghai 17th Radio Factory ?
Thanks !
Flinstone
According to what I have heard from the factory, they don't have any websites or public individual datasheets.
Hi
I'm also interested:
2WD233 douardda 40 France
Thanks
Envoyé de mon GT-N7105 en utilisant Tapatalk
I will take 10 diodes. Will PM technix today.
enut11
Thanks for your efforts!
Count me in for 10 more -
Bertik, France
@GYRO:
I read that thread quite carefully - Zlymex used ffirst 2 (out of 7) listed sources and paid only 1.6 RMB (0.23 USD) - genuine parts (diamond logo)
I made a vague statement that sources on TaoBao charge 1.7 RMB (0.25USD) - the sources I am referring to were provided by Zlymex.
Zlymex used the first 2 sources and received parts with diamond logo (= 17th radio factory of shanghai).
I just wanted to point out that some locals are trying to sell parts at 0.75USD and pay themselves less than 0.25 USD - easy money.
I will source those parts locally in Shanghai - this way we will be sure to source the genuine parts from 17th radio factory.
Any thing wrong with that approach ... ?
Flinstone
address details:
17th Radio Factory of Shanghai:
No.175, Dongjiadu Road, Huangpu District, Shanghai, China +86 21 6377 2411
(My highlight)
Frankly, I don't think that's the case at all, or technix's intention. I am not surprised that the factory would charge a higher factory gate price to supply parts to a 'member of the public' and charge a handling fee for such low volumes. Many (most) chip manufacturers wouldn't be prepared to do business on this basis at all. A factory charging a higher price for a premium quality low noise reference zener variant is not unexpected. Other members have also purchased parts from Taobao / Aliexpress with diamond logos only to find that the delivered parts were just re-marks of inferior ones (as is common practice), the logo is no guarantee at all (which is why Zlymex had to sample test them before shipping!).
The parts that Zlymex
very kindly supplied were very low noise, so undoubtedly from the 17th Radio Factory, however their zero TC current was way in excess of the generic datasheet value for a 2DW233: around 20mA (from my and others' measurements) versus 5mA. They achieve low noise as 'advertised' but given that they came from Aliexpress in plastic bags at low cost could well mean that they had failed a non noise related parametric test. There's no way to tell one way or the other as there was no supply chain traceability. Iirc, the testing that technix has done indicates a the zero TC current of the factory x233 parts is around 5mA. If that proves not to be the case, then people might then have some reason to question.
To repeat, Zlymex was a perfect gentleman in sourcing parts which at the time were not easily available to the community (based on the information available to him from Chinese language forums) and achieved the expected low noise performance. He was not however in the right location to be able to visit the factory and negotiate parts directly.
At the end of the day, it is a matter of trust for individual members to choose whether to purchase in this thread or not. If they wish to question the selling price then they should probably go elsewhere. You should undoubtedly go and do whatever you wish to do without recourse to this thread.
Thanks for the offer.
I'd like to get 50 of 2DW233, US
Thanks for organizing this group-buy.
I'd like to buy 20 of 2DW233, Portugal.
the testing that technix has done indicates a the zero TC current of the factory x233 parts is around 5mA. If that proves not to be the case, then people might then have some reason to question.
To note, the 233 has a more easily manageable TC0 current of around 5mA.
But according to Bertik's tests the desirable series configuration of the 233 (sourced from technix) has a much higher noise figure of 4uV p2p. This compares 0.5uV p2p for the 232.
https://www.eevblog.com/forum/metrology/ultra-low-noise-reference-2dw232-2dw233-2dw23x/msg1113975/#msg1113975To rule out any questions of provenance - this is likely entirely consistent with the influence that higher current plays in lowering noise seen across zener devices - including the ltz1000.
So as Bertik notes, there is quite some tension to obtain a reasonably low TC0 point and low noise at the same time. This is also why I felt it was useful to focus my experiments on a circuit design capable of managing the higher TC0 current point of the 232.
the testing that technix has done indicates a the zero TC current of the factory x233 parts is around 5mA. If that proves not to be the case, then people might then have some reason to question.
To note, the 233 has a more easily manageable TC0 current of around 5mA.
But according to Bertik's tests the desirable series configuration of the 233 (sourced from technix) has a much higher noise figure of 4uV p2p. This compares 0.5uV p2p for the 232.
https://www.eevblog.com/forum/metrology/ultra-low-noise-reference-2dw232-2dw233-2dw23x/msg1113975/#msg1113975
To rule out any questions of provenance - this is likely entirely consistent with the influence that higher current plays in lowering noise seen across zener devices - including the ltz1000.
So as Bertik notes, there is quite some tension to obtain a reasonably low TC0 point and low noise at the same time. This is also why I felt it was useful to focus my experiments on a circuit design capable of managing the higher TC0 current point of the 232.
Please do not forget to specify which part you intend to buy.
@technix
20 of 2DW233 for Australia
enut11
I should clarify: 2DW233 is also OK, though 2DW232 preferred.
Thanks,
bertik
specify which part you intend to buy.
Hi technix
Would it be possible to get a small selection of each type? 10x 2dw232, 10x 2dw233, 10x 2dw234, 10x 2dw235 if it exists? It would be interesting to do some more characterization of each type. I can pay paypal.
Folks that is ordering parts through me, please confirm the order and send me your Email address. (if this is still not working smoothly I will try another method of coordinating this, although if we go down that route you guys will have to pay a bit extra.)
I would be interested:
10 of 2DW232, US
10 of 2DW233, US
Hello Sir,
can you ship to Pakistan?
regards.