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

[caress]

Think about parts counterfeiting the next time you buckle your seat belt on an airplane.

thanks for that rg.   

[J0K3RX]

Think about parts counterfeiting the next time you buckle your seat belt on an airplane.

Think about it the next time you apply the breaks in your car... Luckily my life is not dependent on J201's or I would most likely be dead by now! 

[R.G.]

Sorry for that. I can't *help* thinking about it. Being an engineer all the way down to your toes does that to you. You can't stop thinking "... now, how does that work?"

One of the first counterfeiting issues I'm aware of, dating back to the 1980s and 1990s is counterfeiting bolts and other hardware. I'm pretty sure it was a problem before I became aware of it.

Bolts, nuts, etc. come in grades, depending on the kind of material and its heat treating. Normal hardware store bolts are to grade 8 bolts as cream cheese is to wood in terms of mechanical properties. The higher grade bolts are used where there is a big mechanical load on the bolt and it absolutely, positively has to have all the strength it can. The only external differences are some pips embossed on the bolt heads. Someone long ago found that they could sell bolts for dollars each instead of cents each if the only change they made to their bolts was to emboss the pip-image on the head.

Of course, using cheese-steel for bolts in positions needing ultra-alloy, heat-treated super-steel means things like brake calipers coming off, wings falling off, engines coming loose and rattling around, little stuff like that.

[pakrat]

I'll never fly again. Thanks R.G. 

[puretube]

a little while ago, licensed repair centers of a famous Japanese car manufacturer replaced/sold ORIGINAL manufacturer`s brake discs in europe...


...and had to call them back/re-replace them,
coz`they themselves (= the manufacturer)
thought  they could get them cheaper from the "C"-country...

[gjcamann]

Makes me want to buy everything from smallbear, glad that guy's around.

Are there any JFET array IC's we could use instead of common J201's or other common JFETs?

[midwayfair]

Thiss just became a real issue for me -- I designed something (Cardinal trem) with fixed resistors that result in a distorted FET when real Fairchild J201s are used in place of the Tayda ones I designed the pedal around. Tayda is a common source -- and it's not like it's just a couple that are badly out of spec. Another builder confirmed that Tayda's work right in the pedal, and I tested with basically every one I had.

So I'm trying to decide what to do: Do I recalculate the drain resistors to work with the real part? Put a note in the build doc that if they're using Fairchild ones they might need to socket the drain resistors? Try to figure out what in-spec FET is the best match for the Tayda ones? Give up on the fixed resistors and tell people to socket the drain resistors regardless?

[Dingus]

Thiss just became a real issue for me -- I designed something (Cardinal trem) with fixed resistors that result in a distorted FET when real Fairchild J201s are used in place of the Tayda ones I designed the pedal around. Tayda is a common source -- and it's not like it's just a couple that are badly out of spec. Another builder confirmed that Tayda's work right in the pedal, and I tested with basically every one I had.

So I'm trying to decide what to do: Do I recalculate the drain resistors to work with the real part? Put a note in the build doc that if they're using Fairchild ones they might need to socket the drain resistors? Try to figure out what in-spec FET is the best match for the Tayda ones? Give up on the fixed resistors and tell people to socket the drain resistors regardless?

I personally think you should put a trim pot on figure out the drain resistors yourself and then give the end-user two sets of BOMs depending upon what J201s they have.  At least that's what I would prefer,  as someone who has bought PCBs from you before and plan to again in the future. That or per my previous crossed-out idea, could you not add trimpots in those spaces and have the user calibrate?

[defaced]

I'd call out the details like Bean does in his analog delays.  If you build it with this part, use this resistor.  If you build it with this part, use that resistor.  Simple and effective - assuming the JFETs from a particular source are consistent enough to work with this approach in your design.  Which from what people say, that could be a large contingency. 

[GGBB]

Thiss just became a real issue for me -- I designed something (Cardinal trem) with fixed resistors that result in a distorted FET when real Fairchild J201s are used in place of the Tayda ones I designed the pedal around. Tayda is a common source -- and it's not like it's just a couple that are badly out of spec. Another builder confirmed that Tayda's work right in the pedal, and I tested with basically every one I had.

So I'm trying to decide what to do: Do I recalculate the drain resistors to work with the real part? Put a note in the build doc that if they're using Fairchild ones they might need to socket the drain resistors? Try to figure out what in-spec FET is the best match for the Tayda ones? Give up on the fixed resistors and tell people to socket the drain resistors regardless?

I can only speak as someone who has only a couple of pedals under his belt, but who was hoping to make this a long-term part of my life.  I had hoped to build a couple of things this year that require parts that are getting hard to find (J201, 2N5457).  I would hope that anyone developing new DIY pedals now would design them with reasonably priced and easy to source parts in mind whenever possible.  Why design something if in a year or two no-one can build it anyway?  It wasn't long ago that Fairchild discontinued a lot of through-hole parts, and already our coveted J201s are scarce and priced accordingly.  So why design for them?  I guess the question is, is there any other JFET you could use that is still being made?  And will TO-92 JFETs of any type still be made for much longer?  Maybe we all need to start thinking about SMT.

[thedefog]

I have no trouble believing they fake everything now.

THE BAD
I ordered 50 CA3080 and 50 CA3046 ICs for synth repairs off of eBay (China) from two different sellers...they were all fake. These were compared with known-working ICs, tested in working socketed analog synth circuits. Honestly, I should have known better that the price was too good to be true, so I wasn't completely surprised when I found out, as these are fairly rare ICs.


THE GOOD
I bought LM13700s, PT2399's, ATMega328s, ATTinys, "greenie" Film capacitors, LEDs, and bags of various commonly used transistors all from Chinese eBay sellers that all checked out and worked fine in circuits, the caps had somewhat variable, but acceptable tolerances. Those are all still readily available parts (with LM13700's starting to become scarce).

THE SO-SO
The large bags of 1% tolerance metal film resistors I bought from Chinese eBayers turned out to be more like 10% tolerance....No big deal though for most stuff. There have been very few situations where I absolutely needed to have very tight tolerances for things to work properly (keyboard controller, VCO & VCFs, properly biased circuits, etc.), and for those important ones I always use 0.1% tolerance resistors. 

THE WARNING
The sellers for the parts I received that did not work were goodbuy711 (despite the 99.8% positive rating) and jorgeospina83. Please be advised.

THE LESSON
Personally, I will probably continue to buy certain parts from Chinese eBayers. For anyone that doesn't have the knowledge to know how to spot/test them, it absolutely is not worth taking your chances.

[J0K3RX]

I personally have seen fakes of J201, 2N5457 and 2N5458... I still have a bunch of old J201's and half a reel of the MMBFJ201's which are excellent! I don't mind making the small tombstone adapter boards.. I use some really thin pcb that I got from the guy on ebay that sells pcb. I etch an entire sheet covered with the adapter boards, maybe 50 or 100 then I just pour out the MMBFJ201's and start soldering them to the sheet... When I am done I cut them with scissors since the pcb is super thin it cuts like paper. Or, you could just redesign your layouts for SOT-23.

[pappasmurfsharem]

What saddens me is that a lot of great dirt pedals are designed around J201s.

How will I build my BSIABs in the future? :-(


These are both J201s from Tayda different orders


The one in the left was purchased late last year the right a few months ago


This is the one on the right notice the obvious silkscreen this is not present in the left one

[midwayfair]

I personally think you should put a trim pot on figure out the drain resistors yourself and then give the end-user two sets of BOMs depending upon what J201s they have.  At least that's what I would prefer,  as someone who has bought PCBs from you before and plan to again in the future. That or per my previous crossed-out idea, could you not add trimpots in those spaces and have the user calibrate?

Trimpots have pretty horrible noise performance; and dialing the gain exactly wasn't a concern. However, having two parts with very different gain characteristics made that all go out the window.

I can only speak as someone who has only a couple of pedals under his belt, but who was hoping to make this a long-term part of my life.  I had hoped to build a couple of things this year that require parts that are getting hard to find (J201, 2N5457).  I would hope that anyone developing new DIY pedals now would design them with reasonably priced and easy to source parts in mind whenever possible.  Why design something if in a year or two no-one can build it anyway?  It wasn't long ago that Fairchild discontinued a lot of through-hole parts, and already our coveted J201s are scarce and priced accordingly.  So why design for them?  I guess the question is, is there any other JFET you could use that is still being made?  And will TO-92 JFETs of any type still be made for much longer?  Maybe we all need to start thinking about SMT.

Well, J201s exist in SMD. It's possible to solder legs to them and plug them into a through-hole PCB. So there's no reason not to design a circuit around J201s. There are also MILLIONS of these things around. I suspect that the present scarcity is partly an illusion caused by how recent Fairchild's discontinuation is. Everyone's out buying as many as they can get their hands on, which drives up the price and encourages counterfeiting. Commericial products will eventually adapt, then us DIYers will probably go on for years.

Through-hole parts in general are becoming obsolete; suggesting that we shouldn't design around a particular FET is like suggesting that we stop designing around through-hole resistors.

Also: A Fairchild J201 can be had for 50c from the store here, and 55c from Smallbear. That's not an expensive part -- it's the same as a couple good capacitors. It's just not a 2c transistor like a 2N3904.

[GGBB]

Through-hole parts in general are becoming obsolete; suggesting that we shouldn't design around a particular FET is like suggesting that we stop designing around through-hole resistors.

With all due respect Jon, I think that's a very inaccurate comparison.  A resistor is just a resistor, a FET is nowhere near as generic and the J201 seems to be one that has no good substitutes in specific applications.  Would you design a DIY pedal, with the intention of selling either PCBs or complete kits for it, or even just for the joy of having a pedal out there that DIYers like to build, if one or more parts were either too scarce or too expensive to make the enterprise worthwhile for the mass of DIYers?  Maybe the J201 isn't quite at that place right now, but it appears to be heading there at a rapid pace and my guess is that it will be there within the next few years or at least long before through-hole itself is completely unfeasible. 

And it's not just a matter of availability period, it's easy availability.  The biggest pain in building pedals I am finding is getting the parts.  I already spend as much on shipping as I do on parts, simply because I have to order some things from here, some things from there etc.

The DIY community needs your designs, Jon!  Please don't make it difficult to build them.

[J0K3RX]

I think the bottom line at this point in time is to buy them from a well known, respectable and reliable source like the DIYSB store or smallbear! There may be others out there as well, maybe a list of good reliable "without a doubt" sources would be helpful!?

Buy from ebay or china or anywhere else and it's your choice... go for it if you're a person who likes to roll the dice. Personally, I would rather pay the extra 10 or 20 cents per part if I know I will be getting the real deal and not some turd painted to look like a steak...

[garcho]

I really wouldn't worry about the possibility of the J201 turning into a OC44. Outside of manufacturers and warehouses, there are so many pedal makers in the world, think how many TO-92 J201s are sitting on benches? $0.50 is not exorbitant price to pay. What do you foresee as the lowest price five years from now? 2 bucks? It's still way cheaper than germanium transistors and there aren't any shortage of those projects here.

[pakrat]

Just last week I recieved genuine j201's from Smallbear and they have plenty in stock. After recently recieving j201's from Tayda that look much like the "fake" ones pictured, I decided to order a bunch more from the DIYSB store. I guess you can't have too many if you're into dirt boxes and high gain circuits.

[bacilus]

I check the  Smallbar, but this time no stock...

[pakrat]

That's strange, I thought Smallbear had over 400 of them when I ordered, looks like he has only 2 left from Vishay. The DIYSB store still has stock, better grab them while you can!