JFET’s J113, 2SK170, 2N5457 and others

I know I still would like to buy the lowest noise jfets for the application, I will use them at various circuit not just for this place, and some will be amplifiers.
Just to make sure I understand, will I get the same noise with all jfets, in this application ?
Will it be buried under the other noise, or will it add up, noticeable or not ?
By the way the signal will be amplifier after.
 
Sam Groner (Linear Audio Volume 3) pointed out the noise "optimum" with respect to drain current and used 1mA per device (BF862) for his 400pV amplifier. He also kept Vds at 2.4V to eliminate device heating.
 

Attachments

  • scan0015.jpg
    scan0015.jpg
    135.4 KB · Views: 382
  • Like
Reactions: 1 user
Thank you very much this is gold, that is what I want to learn.

J113 to92 look like the perfect price/performance/availability I will start with this one.
I am looking between the 113 and for buffer alone these :
- 2N4117/A, 2N4118/A,2N4119/A
https://www.mouser.fr/datasheet/2/676/jfet-2n4117-2n4118-2n4119a-interfet.r00-1649084.pdf
- J210, J211, J212
https://www.mouser.fr/datasheet/2/676/jfet-j210-j211-j212-interfet.r00-1649154.pdf
I don't want to go look for discontinued devices.


1mA to 2mA seems to be a universal sweet spot even for tubes !
 
Went to Mouser and ordered a fistful of ON J113 Jfets. According to the ON product data sheet the J113 has a min of 2ma Idss, no max is given. According to the Mouser page the J113 Idss range is 2ma to 9ma. I hope that this range is not to far from the truth.

The J113 are cheep and easy to get, so we will test them first.

Thanks DT
 
Went to Mouser and ordered a fistful of ON J113 Jfets. According to the ON product data sheet the J113 has a min of 2ma Idss, no max is given. According to the Mouser page the J113 Idss range is 2ma to 9ma. I hope that this range is not to far from the truth.

The J113 are cheep and easy to get, so we will test them first.

Thanks DT
Few years ago i buyed 500 pcs.
53 pcs 9-13mA Idss
182 pcs 13-17 mA Idss
rest 17-26 mA idss

Measured at 15vds, same as Vds at datasheet.
Please compare your batch. Maybe there is difference related to Idss spread.