Did I just buy some original TI 2n3819's?
« on: July 09, 2020, 06:22:53 PM »
I've been buying 2n3819's off eBay since I picked up about 25 central-semi brand from Mouser that were useless to me (all 17.5+ idss). I thought I'd have better luck buying smaller amounts from multiple sources. I took a chance on some simply labeled as "NOS 2n3819 JFETs".

Imagine my surprise when I got them in the mail, took them out of the package, and saw "TI" printed on all of them. They look ancient, the leads are a little dirty. But they are from two factories, some from Singapore and some from Korea. Country names are printed on top. The Singapore ones have perfectly round wire legs. The Korea ones have flat, more modern looking legs.

I've never actually come across any TI 2n3819's before. I don't know what they look like. From my searching online I found a single photo that didn't match these, but I've seen photos of other genuine Texas Instruments FETs that do look the same as these. Same font, same legs, same blue/green paint dots on front.  Can anyone enlighten me here? Do I have genuine TI JFETs or just some old generic brand ones?


Khron

Re: Did I just buy some original TI 2n3819's?
« Reply #1 on: July 09, 2020, 11:23:37 PM »
Maybe? They do look quite oldey-styley, though (possibly NOS?).

http://www.transparentsound.com/transistors/vintage-transistors/texas-instruments/texas-instruments.htm

That being said, i've yet to comprehend the... "obsession" with ONE particular part number, though  ??? But i guess i'm just weird like that...
Khron's Cave - Electronics - Audio - Teardowns - Mods - Repairs - Projects - Music - Rants - Shenanigans

Ricardus

Re: Did I just buy some original TI 2n3819's?
« Reply #2 on: July 10, 2020, 12:55:58 AM »
I went the eBay route 18 months ago and didn't find one legit 3819. They were all phony.

Now I believe I heard John Peluso once say he really liked the Motorola 3819s. He thought Neumann was using those. I did manage to find some legit NOS Motorolas from some vintage house last year, but I don't remember which one.
Audio mastering for hire..

Re: Did I just buy some original TI 2n3819's?
« Reply #3 on: July 10, 2020, 11:00:31 AM »
Maybe? They do look quite oldey-styley, though (possibly NOS?).

http://www.transparentsound.com/transistors/vintage-transistors/texas-instruments/texas-instruments.htm

That being said, i've yet to comprehend the... "obsession" with ONE particular part number, though  ??? But i guess i'm just weird like that...

No specific part number, these are just the FETs used in U87's, and I build U87's. I've had pretty bad luck with the current manufacturer for some reason. And I tend to have good luck with Fairchild ones. When I bought these, I assumed they were Fairchilds. TI stopped making these in the 80s as far as I'm aware. It's just strange to find these on some random eBay listing.

Re: Did I just buy some original TI 2n3819's?
« Reply #4 on: July 10, 2020, 11:02:53 AM »
I went the eBay route 18 months ago and didn't find one legit 3819. They were all phony.

Now I believe I heard John Peluso once say he really liked the Motorola 3819s. He thought Neumann was using those. I did manage to find some legit NOS Motorolas from some vintage house last year, but I don't remember which one.

Really? I've gotten plenty of genuine Fairchild 3819s from eBay. I typically only buy from US sellers with photos of the actual lot of FETs instead of some generic photo. But I have heard of people getting fakes before, mostly from Chinese sellers. How did you know they were fake?

Ricardus

Re: Did I just buy some original TI 2n3819's?
« Reply #5 on: July 10, 2020, 09:13:46 PM »
Really? I've gotten plenty of genuine Fairchild 3819s from eBay. I typically only buy from US sellers with photos of the actual lot of FETs instead of some generic photo. But I have heard of people getting fakes before, mostly from Chinese sellers. How did you know they were fake?

 Because my transistor tester said they were BJTs. I found some vintage Fairchilds also at a vintage house. The pair of 87s I made have those in them. The next pair I build will use the Motorolas.
Audio mastering for hire..

Lowfreq

Re: Did I just buy some original TI 2n3819's?
« Reply #6 on: July 11, 2020, 05:26:31 PM »
I bought some TI 2n3819's off eBay last year, and they look just like the ones with the little paint stripes on the back.
I don't know if they're genuine or not, but I'm pretty sure I got them from the US or Europe. Ebay history won't give me the details, but I'm pretty sure it wasn't china.

I haven't used them in a mic yet, but I did idss measurements and sorted them into pairs, and most of them were really good, with the lowest around 4.5mA and the highest around 13mA. Most of them were around 6 or 7mA, so very useable values from the lot I got.

EDIT: I figured out that I got them from Greece.
« Last Edit: July 11, 2020, 05:33:33 PM by Lowfreq »

Re: Did I just buy some original TI 2n3819's?
« Reply #7 on: July 11, 2020, 08:23:59 PM »
I bought some TI 2n3819's off eBay last year, and they look just like the ones with the little paint stripes on the back.
I don't know if they're genuine or not, but I'm pretty sure I got them from the US or Europe. Ebay history won't give me the details, but I'm pretty sure it wasn't china.

I haven't used them in a mic yet, but I did idss measurements and sorted them into pairs, and most of them were really good, with the lowest around 4.5mA and the highest around 13mA. Most of them were around 6 or 7mA, so very useable values from the lot I got.

EDIT: I figured out that I got them from Greece.

Interesting! Mine were from France. And same with the idss measurements. Lowest was around 4.5, highest was 7.5 so all were very usable.

Re: Did I just buy some original TI 2n3819's?
« Reply #8 on: July 13, 2020, 04:00:39 PM »
Because my transistor tester said they were BJTs. I found some vintage Fairchilds also at a vintage house. The pair of 87s I made have those in them. The next pair I build will use the Motorolas.

UPDATE: Finally got around to testing & biasing my new batch of FETs. Every single "Fairchild" one I have is a dud... They won't pass any signal. Identical setup with identical circuit has zero issues with my older Fairchilds, NOS TI's, etc. I suspect they aren't even JFETs. This is the first time I've ever had any issues with sourcing from Ebay. I'm a bit disappointed. I guess my real Fairchilds from Ebay in the past were more the exception than the rule...

Ricardus

Re: Did I just buy some original TI 2n3819's?
« Reply #9 on: July 14, 2020, 12:37:28 PM »
UPDATE: Finally got around to testing & biasing my new batch of FETs. Every single "Fairchild" one I have is a dud... They won't pass any signal. Identical setup with identical circuit has zero issues with my older Fairchilds, NOS TI's, etc. I suspect they aren't even JFETs. This is the first time I've ever had any issues with sourcing from Ebay. I'm a bit disappointed. I guess my real Fairchilds from Ebay in the past were more the exception than the rule...

I called Ebay's 800 number and got refunds on every fake order of those (2 in total).
Audio mastering for hire..


 

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