The don't fake JFETs now.......do they?

[electrosonic]

How are FETS manufactured? Are they manufactured and then sorted and labelled based on their specs or does a manufacturer make a batch of J201's. From what was described in the original post, the jfets don't seem fake - just mislabelled. Is someone relabelling jets or buying out of spec jfets and selling them as if they are good?

Andrew.

[darron]

I think similaraly to Paul. It's hard to imagine a company in China intentionally trying to manufacture replicas, and then sell them at a similar cheap rate. I was thinking more along the lines of rebranding something already less than average. Maybe these are restamped rejects from another manufacturer for example.

At any rate, right away I noticed that the package wasn't like the usual ones I see from all the Fairdchilds that I get in. And the print and logo looked a bit different.

[Paul Marossy]

At any rate, right away I noticed that the package wasn't like the usual ones I see from all the Fairdchilds that I get in. And the print and logo looked a bit different.

Yeah, you can see that in the pictures for sure.

[Toney]

  Paul, I hesitated even posting this at the start because it seemed unlikely that anyone could be bothered, but apparently restamping is pretty rife in China. The relabeled BBD situation has been going on for some time, mostly as noted MN3008 relabeled as MN3005 with lots of examples. It seems its so bad that most of the ones found on Ebay are suspicious.
Buying power is obviously relative. A $30 sale is 190 Chinese Yuan Renminbi (CNY). I had a quick Google and found this: http://en.wikipedia.org/wiki/List_of_minimum_wages_in_China_%28PRC%29 so it seems an average minimum monthly wage for Beijing or Shanghai is 1270 CNY and that's approx. 293 CNY per week so looks like its well worth it. A $30 sale is more than 65% of the minimum weekly wage.

About 70% of the batch I have are close-ish to the extreme end of the scale for J201 values for Vgs off but well out for Idss tested against a couple of differently sourced "real" Fairchild J201s which came in right within expected spec.
I guess a couple of possibilities are:

They are factory rejects, intended to be disposed of.
They are relabled devices of some kind stamped J201 as its a popular seller on the bay and specs were vaguely plausible.

But thats just one person testing (me!) and I could be wrong (ever possible lol) so if other wanted to do the Fetzer valve Idss test that would add to it.

[Earthscum]

That actually makes me wonder if they aren't some other "cheaper" jfet... I'm suspecting J202's restamped, based off what you guys are saying.

J201 - J202 / MMBFJ201 - MMBFJ203 N-Channel General Purpose Amplifier DATASHEET


201 VGS (off) = 0.3-1.5 V  IDSS = 0.2 - 1.0 mA
202 VGS (off) = 0.8-4.0 V  IDSS = 0.9 - 4.5 mA

You can see there's an overlap of 0.7V that they could both be the same and still "within range", but only 0.1mA overlap in IDSS spec. An "In Spec" 202 could have similar VGS as a 201, but the IDSS would be way out.

Reason I'm thinking this is because maybe they have a ton of the 202's that nobody buys, so they are just restamping them to dump them at a penny or 2 higher than they normally could.

[Toney]

 Yep, if they were marked J202, they would be in spec as tested.
From memory They were averaging ~2 mA Idss vs "real" J201 which were approx 0.4-6mA from both samples.

I considered emailing Fairchild to see if I could dig up any info as to whether the case was one they manufacture. It's physically different from the other known "real" ones in several ways.

[Paul Marossy]

Buying power is obviously relative. A $30 sale is 190 Chinese Yuan Renminbi (CNY). I had a quick Google and found this: http://en.wikipedia.org/wiki/List_of_minimum_wages_in_China_%28PRC%29 so it seems an average minimum monthly wage for Beijing or Shanghai is 1270 CNY and that's approx. 293 CNY per week so looks like its well worth it. A $30 sale is more than 65% of the minimum weekly wage.

That's the thing about China that is confusing. You see on TV all these fancy buildings in their major cities which definitely (to me) gives the appearance that they are milking away America's wealth and jobs for domestic workers, and 90% of everything in Walmart, Target or just about anywhere else we buy stuff from was made in China. And yet you have people there with an average minimum income of only like $150?!?! The must be a HUGE gap between the rich and poor in that country. Not only that but the pollution in Beijing is just absolutely appalling. Smog so thick that you can't even see a block away. I wonder how much they contribute to global warming? Anyway, I sure am tired of China these days.

[Govmnt_Lacky]

Do you ever wonder if items for sale in China are stamped:

"Made around the corner" 

[Paul Marossy]

So I got some CA3080s from this "polida" seller on eBay. They aren't the same as what was in the picture on the auction but the markings on these are very similar in color and brightness to the pictures of the J201s at the beginning of this thread. I don't recognize the manufacturer markings on these chips I got (supposedly Intersil I guess) but they work.

[Earthscum]

Hey Paul... sometimes, I think the Chinese just build crap to keep people busy, which would definitely make for a surplus of parts.

Seriously... what a waste of resources.
http://www.dailymail.co.uk/news/article-1339536/Ghost-towns-China-Satellite-images-cities-lying-completely-deserted.html


eta: just makin clear: nothing against Chinese people, more of the people at the top who make these decisions (or is that at the bottom? Sometimes both?)

[Toney]

Just an update:
I actually managed to get a PayPal full refund for these.
Surprised! I called them up and explained the shipping would be over 70% of the purchase price and they refunded me.
Major PITA but OK in the end.

[imzuker]

I Made a dr boogie with the left ones and it sounded like that
http://www.youtube.com/watch?v=jG1UsXuVqY4
guess it explains the lack in gain i got

[mac]

I would not buy rice from China...

mac

[Paul Marossy]

I would not buy rice from China...

mac

These days trying to buy stuff not made in China is like trying to buy food without salt or sugar in it, very hard to do. With the pollution in China, I wouldn't want to buy rice from there either.  

[KMG]

Most of semiconductors now manufactured in south-east Asia.

NXP Established: 2006 (formerly a division of Philips)
50+ years of experience in semiconductors

Look for example at datasheet.
http://www.nxp.com/documents/data_sheet/BAT54_SERIES.pdf
MARKING CODE(1)
1.∗ = p : Made in Hong Kong.
∗ = t : Made in Malaysia.
∗ = W: Made in China.

[Pyr0]

Lets be fair here guys, the problem is not with buying stuff made in China, but buying stuff from some Chinese EBAY sellers.

[Paul Marossy]

Lets be fair here guys, the problem is not with buying stuff made in China, but buying stuff from some Chinese EBAY sellers.

I have a problem with either one.

[deadastronaut]

i must just be lucky, everything ive bought from china, hong kong, japan, thailand etc etc...have all be fine...

in my experience they never want to piss you off and will do anything to avoid bad feedback etc...

[haveyouseenhim]

I saw this thread after i ordered some  20 j201 and 20 4558d...    I dont know how to test them but i can say for sure that the 4558 sounds HORRIBLE!



any ideas on what i should put in the package to send back to them (nothing illegal)  (preferably insulting or gross)

[Toney]

Well they certainly have "the look" but to be certain it would be good to test them. It's good to have some data to refer to when you ask for a refund.
The J201's are pretty quick and easy to test for Vgs of and drain current.
I don't know of any quick tests other than A/B testing for the opamps. Perhaps you could email JRC and ask them if they produce 4558's in that package style?