BF862 Preamp

[scott wurcer]

No, they are all pretty much close in Idss (12-14mA, most of them about 13mA)


Right
You can use lower value for gate stopper, Scott Wurcer says that even ferrite bead is enough

I just suggested it, syn08 built and tested the SMT ferrite idea. Massively paralleled BF862's are "guaranteed" to oscillate without some considerations since they are designed for AM radios not audio.

 

[juma]

...poor eyesight and shaking hands keeps success at bay.....

JT, if you don't find a helping hand in the neighborhood just PM me your address again and I'll send you these JFETs already mounted on adapter boards.

 

[Samuel Jayaraj]

Juma, where can I get BF862s. Not available where I live.

 

[juma]

Juma, where can I get BF862s. Not available where I live.

mouser.com
digikey.com
farnell.com
newark.com
and many other online shops....

 

[npapp]

Alas, Old Age (and its consequences) is keeping me from this project. If you go to post #10 you will see a strip of miniature PCB's made for the BF devices used in this project. I have one of these strips and the BF862's to go on the strip.

I have made numerous attempts to solder the devices to the strip but poor eyesight and shaking hands keeps success at bay. Believe me, this is not a one or two attempt scenario but a concerted daily ongoing trial and error thing that creates suicidal tendencies!!

There are 14 pads on the strip as shown in post#10 . What I seek is an individual with the ability and courage to solder these together,with a barter deal of some sort to show my gratitude. It would be best if that (wonderful) person were in the US to keep it more manageable.

I can furnish solder and a flux pen for the job.

Hi SH,
I am happy to solder these together for you if you do not already have a hand. No need for barter or the rest, just send the pcb and BF862s. PM me and I will send you my home address.

Nick

 

[sandyhooker]

JT, if you don't find a helping hand in the neighborhood just PM me your address again and I'll send you these JFETs already mounted on adapter boards.

John..Thanks so much for the offer.It appears that I found someone on this side of the pond to help. 🙂

JT

 

[sandyhooker]

Hi SH,
I am happy to solder these together for you if you do not already have a hand. No need for barter or the rest, just send the pcb and BF862s. PM me and I will send you my home address.

Nick

Email sent

 

[sandyhooker]

NPAPP..Hopefully I used the correct email address. If you have''nt received p[lse post..

thanks

 

[npapp]

JT, You did use the right email. It was a busy day at work but you should have my address now. Please let me know if my email did not come through.
N

 

[npapp]

Juma, are you willing to share the board files? I would like to change the pads to smd for the jfet and have a few boards made.

 

[juma]

Juma, are you willing to share the board files? I would like to change the pads to smd for the jfet and have a few boards made.

Here you are - a zipped gerber file for 160x100 mm (standard Euro format) PCB:

 

[juma]

Here you have a zipped Sprint-Layout 5.0 design file:

 

[npapp]

Hi Juma, I should have been more specific, I am hoping for the board files for the full preamp with the shunt reg you attached to post #24. Actually if you have the sprint layout for that board it would be even better.
Thanks, Nick

 

[juma]

....I should have been more specific....

Yes you should 😉
Here you are:

 

[npapp]

 

[ucciopino]

Excellent

 

[npapp]

I modified Juma's original board to accept SMD or through hole options for the BF862. Will someone with a trained eye please review the board and let me know if revisions are necessary.

If this board passes the QA of the forum and with Juma's permission I may do a small proto GB. Please let me know if you are interested and I can check pricing for a limited run.

Thanks, Nick

 

[npapp]

Here it is again with mounting holes

 

[juma]

AFAIC, you did a nice job Go ahead with GB 🙂

 

[jleaman]

Agreed, looks nice | : )