OPEN SOURCE DIY Mic Project - ORS 87 - Stripped Down u87

[Juan Vargas]

1​

LSK189​

JFET​

Ultra Low Noise, Low Drift, Single N-Channel JFET​

722-LSK189TO923LBK​

LSK189-TO-92-3L-BK​

It's really my mistake... But why does it work? ))))

oh man this is weird I'm not sure what to tell ya on the next board make sure the orientation the FET face is correct, you was not drinking hot fire Vodka dear friend I see you

 

[Korablev]

I fixed this annoying oversight, the microphone works well again! Apparently JFet can function in different positions, and this is very good! ))) P.S. Although no. Now the microphone produces an ultra-low signal.

 

[Juan Vargas]

I fixed this annoying oversight, the microphone works well again! Apparently JFet can function in different positions, and this is very good! )))

nice man hey thank you for sharing the build and pictures this make me so happy to see it working

 

[Khron]

Apparently JFet can function in different positions, and this is very good! ))) P.S. Although no. Now the microphone produces an ultra-low signal.

Have you re-done the biasing?

 

[Korablev]

nice man hey thank you for sharing the build and pictures this make me so happy to see it working

Yes, JFet works both ways, and the ultra-low signal was due to the fact that it was necessary to set the correct offset with the trimmer.

 

[Juan Vargas]

Yes, JFet works both ways, and the ultra-low signal was due to the fact that it was necessary to set the correct offset with the trimmer.

Korablev can I ask for permission to use your build photos on my YouTube channel CoquiAudio? I just want to show those nice photos

 

[Korablev]

Korablev can I ask for permission to use your build photos on my YouTube channel CoquiAudio? I just want to show those nice photos

Well of course yes! I'm always very happy to help with something!!!

 

[Juan Vargas]

thank you so much Korablev this means a lot to "muchas gracias" = thank you so much, and have a great good day dear friend and have fun

 

[Korablev]

A very important addition, which was mentioned in this thread on pages 5-8.
Important.
If you are using a JFET LSK189, it has a reverse pinout, unlike the 2n3819.
It is important to pay attention to this point, since the LSK189 will work in an inverted state, but its operating mode will be incorrect.




In the end, I left the JFET LSK189 in this state:



In total, I desoldered the part and bent the central leg several times. But the legs turned out to be of high quality and withstood all the abuse. This does not always happen, and there are cases when the leg breaks off near the case, which is very, very bad. You need to be very careful.

 

[Juan Vargas]

A very important addition, which was mentioned in this thread on pages 5-8.
Important.
If you are using a JFET LSK189, it has a reverse pinout, unlike the 2n3819.
It is important to pay attention to this point, since the LSK189 will work in an inverted state, but its operating mode will be incorrect.

View attachment 144415

View attachment 144416
In the end, I left the JFET LSK189 in this state:

View attachment 144417

In total, I desoldered the part and bent the central leg several times. But the legs turned out to be of high quality and withstood all the abuse. This does not always happen, and there are cases when the leg breaks off near the case, which is very, very bad. You need to be very careful.

oh ok thank for let me know so Q1 in that orientation works correctly? is that the case then I have to installed like that then ok ok anyway the GATE leg will be in a floating mode gotta go back and read 5 - 8

 

[Khron]

Q1 in that orientation works correctly? is that the case then I have to installed like that then

Well, it depends what part number (and pinout) the JFET is, doesn't it? I don't think it's wise to make any "blanket statements"... The datasheet for the respective part number is "holy", and that's the end of it (imho).

 

[Juan Vargas]

Well, it depends what part number (and pinout) the JFET is, doesn't it? I don't think it's wise to make any "blanket statements"... The datasheet for the respective part number is "holy", and that's the end of it (imho).

"blanket statements"... agree totally yes, I will know after I put it together

 

[mic test]

hello can I replace the lsk 189? BF862 Noise level Very low (approx. 0.5 nV/√Hz)

 

[Juan Vargas]

but BF862 is no longer in production and is a SMD device?

 

[mic test]

ja du hast recht es wird nicht mehr hergestellt ja smd wäre auch kein problem vielleicht finde ich noch andere mit guten rauschwerten ich habe einen j211 fet getestet der war extrem leise im vergleich zum lsk 189 ich frage mich warum die so unterschiedliche pegel angeben steht das auch irgendwo

 

[Khron]

ja du hast recht es wird nicht mehr hergestellt ja smd wäre auch kein problem vielleicht finde ich noch andere mit guten rauschwerten ich habe einen j211 fet getestet der war extrem leise im vergleich zum lsk 189 ich frage mich warum die so unterschiedliche pegel angeben steht das auch irgendwo

I thought English was the official language of this forum..? Despite whatever one-way auto-translating your web browser might be doing...

 

[Juan Vargas]

mic test at least translate to English too I think is the first time I see that dialect

 

[eso]

I thought English was the official language of this forum..? Despite whatever one-way auto-translating your web browser might be doing...

ja du hast recht es wird nicht mehr hergestellt ja smd wäre auch kein problem vielleicht finde ich noch andere mit guten rauschwerten ich habe einen j211 fet getestet der war extrem leise im vergleich zum lsk 189 ich frage mich warum die so unterschiedliche pegel angeben steht das auch irgendwo

yes you are right it is no longer manufactured yes smd would also be no problem maybe I can find others with good noise values I tested a j211 fet which was extremely quiet in comparison to the lsk 189 I wonder why they specify such different levels is that also written somewhere


Google is your friend.

eso