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

[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

 

[Juan Vargas]

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

 

[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

 

[Khron]

or send the file to my e-mail

It's usually not a great idea to publicly list your email address in plain text (unless you're a fan of getting tons and tons of spam emails)...

 

[Juan Vargas]

It's usually not a great idea to publicly list your email address in plain text (unless you're a fan of getting tons and tons of spam emails)...

ok I deleted

 

[Juan Vargas]

I just hope those humongous things fit inside that mic body...

yes Khron it did fit I just finish the build

 

[Juan Vargas]

I just finish the build and a few minor problems I got the 1uF main cap with different sizes options was too tall but I manage to close the mic body, and the cylinder has a conical shape and was too close to that cap also I place the Q1 too far away from the insulator on my layout design, since I don't have proper tools or better say just a digital multi meter I set the FET to 15V DC oh the 1G ohm resistor is no problem. please let me know if this is ok is the first time that I'm building a microphone

I use 150pF for C6A tested and I like the way it sound I then add a 10pF cap in parallel with C6A and I didn't like the sound I just cut one of the legs "no m gusto para serles sincero" = "I didn't like it to be honest" the other cap C5A remains the same value 33nF the R* I haven't installed yet, and then updated Layout move Q1 higher and on trim pot I add a second option of trim pot.

In my opinion this was one of the best experience building this design I'm not and expert on music or sound production but this is better than my MXL 770 old mic lovely! later I'm gonna populated the first PCB version for this mic body the blue one YES Khron the wiring is horrible I see you! I know is 22 AWG PTFE should be like 26 to 28 AWG I will keep posting later for the blue TF22 mic body later good day guys