By the way, I see 2SK209GR measures very consistent straight out from the reel as a member recently posted some results there: https://www.diyaudio.com/forums/pass-labs/329240-waynes-ba-2018-linestage-114.html#post6192893
When needing something fairly close to 2SK170 for noise and Vgs (off) spec but also less transcondcutance is tolerable in a specific application, it looks good.
When needing something fairly close to 2SK170 for noise and Vgs (off) spec but also less transcondcutance is tolerable in a specific application, it looks good.
Quite right. 2SK117 or alike parts are a useful alternative depending on the situation. That is why I opted in the DCG3 line preamp for a then forgotten and not at all sought after NOS NEC dual monolithic with much alike to 2SK117 characteristics. Its a matter of balancing enough performance vs viability for a repeatable project. Alas, not anymore, prices went up and fakes appeared. Better go even with adapters and known quality Toshiba SMD from reliable mega stockists these days.
Ahh, that's true, you could swap T2 for a darlington or add an LED/diode, but that would be changing the design 
Tried things back then, there are implications. I will not expand. Its a thread about about JFETS.
My local shop suggested BS170 as a replacement. They sell them for 45 cents. Should I stockpile them and give it a try?
The BS170 is not a JFet.
So no, and be very skeptical about any other recommendations from that shop.
So no, and be very skeptical about any other recommendations from that shop.
I used google.com to search for web pages that discuss the BS170 transistor. One of the pages it found was a datasheet from the manufacturer, ON Semiconductor.
After comparing the BS170 datasheet with the manufacturer's datasheet of the 2SK170, I think you were right to question the advice of your local shop.
https://www.onsemi.com/pub/Collateral/BS170-D.PDF
After comparing the BS170 datasheet with the manufacturer's datasheet of the 2SK170, I think you were right to question the advice of your local shop.
https://www.onsemi.com/pub/Collateral/BS170-D.PDF
B&D Ent Toshibas
I've bought 8 pairs from Bdent: 2SK170BL+2SJ74BL
While they're not matched sets, i've read elsewhere that they're pretty close and genuine. Should I be concerned about the different ranking(?) number or batch # between each complementary part. The J74 are 8H & the K170 are 8G.
Of course one can plot curves for each JFet but then varying room temps or even blowing on them while doing measurements is a concern; and the testing won't be accurate.
Advise on the photos taken?
https://i.imgur.com/0m8707d.jpg
One thing others have not mentioned is the left over flux at the top of the leads (see in photo). Of the 3 legs you can see the brown flux which i'm not sure if the 'FAKE' ones would have the same assembly process? Just something to consider about when looking at fakes.
Back side has the round molding mark.
Top side molding mark. Also the line that others mentioned is the molding seam.
I've bought 8 pairs from Bdent: 2SK170BL+2SJ74BL
While they're not matched sets, i've read elsewhere that they're pretty close and genuine. Should I be concerned about the different ranking(?) number or batch # between each complementary part. The J74 are 8H & the K170 are 8G.
Of course one can plot curves for each JFet but then varying room temps or even blowing on them while doing measurements is a concern; and the testing won't be accurate.
Advise on the photos taken?
https://i.imgur.com/0m8707d.jpg
One thing others have not mentioned is the left over flux at the top of the leads (see in photo). Of the 3 legs you can see the brown flux which i'm not sure if the 'FAKE' ones would have the same assembly process? Just something to consider about when looking at fakes.
Back side has the round molding mark.
Top side molding mark. Also the line that others mentioned is the molding seam.
I consider Bdent a trusted supplier. I've ordered a lot from them and never gotten a counterfeit part.
The '8H' vs '8G' are just date codes. The 'BL' part is the grading.
The '8H' vs '8G' are just date codes. The 'BL' part is the grading.
I have ordered 50 of these Toshiba JFETs from this source and all were legit. Enjoy your purchase.
Has anyone done an experiment to see if you can hear any difference between the original 2SK170/2SJ74 and the replacement LSK170/LSJ74?
I'm in very early theoretical preliminary planning stages of an Aleph J, so really I guess I'm just wondering about the 2SJ74 vs LSJ74.
I'm in very early theoretical preliminary planning stages of an Aleph J, so really I guess I'm just wondering about the 2SJ74 vs LSJ74.
Absolutely guaranteed genuine Toshiba item. Taken out of Toshiba bag to photograph. Height of the body is 4.5mm and width across widest part is 5mm. Legs are 13mm long. 
@ gazzagazza: Nice to meet another Kiwi here (i'm in Chch).
and here where the JFets went: (Sony VFET v1):
and here where the JFets went: (Sony VFET v1):
Greetings to all experts,
I found 8 NOS 2sk170GR on the shelf (bought in 2011 for 1 EUR from ELFA 😀) - I measured Idss with 9V PSU - 4 is in the range of 4-5.5 mA and 4 is in the range of 6 -6.5 mA. Can I use the last 4 to say B1 or ACA instead of BL or Idss is too low?
tnx
I found 8 NOS 2sk170GR on the shelf (bought in 2011 for 1 EUR from ELFA 😀) - I measured Idss with 9V PSU - 4 is in the range of 4-5.5 mA and 4 is in the range of 6 -6.5 mA. Can I use the last 4 to say B1 or ACA instead of BL or Idss is too low?
tnx
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