J201 listed as obsolete at mouser and no suggested replacement? halp.

[duck_arse]

can seven of nine do my assimilation? I don't even much like j201's.

anyone else ever used j210'S?

[Jdansti]

MMBFJ201 - It's inevitable, you must conform or be assimilated 

Resistance is futile!!!

R = U/I 

+1 

Somehow, capacitance is futile just didn't sound right.

can seven of nine do my assimilation?

It was tempting to post a seven of nine!!!

BTW-Sorry-haven't used the J210, but have used the J112. I'm no sure how well a J112 would work in a circuit designed for J201.

[joejoe226]

newb here, late to the party.

I want to build the ROG Supreaux.  Can I use...

MMBFJ201 instead of the J201?
and
MMBF5457 instead of the 2N5457?

here's a 2N5457 link: http://physics.gac.edu/~huber/classes/phy270/SpecSheets/2N5457.pdf

thanks,

joejoe

[Ice-9]

newb here, late to the party.

I want to build the ROG Supreaux.  Can I use...

MMBFJ201 instead of the J201?
and
MMBF5457 instead of the 2N5457?

here's a 2N5457 link: http://physics.gac.edu/~huber/classes/phy270/SpecSheets/2N5457.pdf

thanks,



joejoe

Yes, therethe same just in an SMD package.

[mth5044]

newb here, late to the party.

I want to build the ROG Supreaux.  Can I use...

MMBFJ201 instead of the J201?
and
MMBF5457 instead of the 2N5457?

here's a 2N5457 link: http://physics.gac.edu/~huber/classes/phy270/SpecSheets/2N5457.pdf

thanks,



joejoe

Yes, they're the same just in an SMD package.

So no, you can't use them instead of the other in the sense you can't drop them in. You will need to either build a small adapter board that takes the SMD to a through-hole, or create a new PCB.

[smallbearelec]

I want to build the ROG Supreaux.

Common TO-92 JFets can be found here at reasonable prices:

http://www.smallbearelec.com/servlet/Categories?category=Transistors%2C+FETs+%26+MOSFETs

and I bought all of them from well-known distributors before Fairchild pulled the plug.

[M23Bomber]

Hello  

A small list of replacements for the J201 in TO92 case:

J201- 2N5484, 2N5457, 2N5485, NTE458, BF245A, MPF102, 2sk117, 2SK170

Please double check with the datasheets to confirm the pinout and build a JFET MAtcher this will be a great tool with JFETS.

All of these possible replcements have a Vpo ( pichoff voltage) that allows them to be used for guitar effects, and maximum Vds that allow them to be used with 9VDC bateries.

Obviously the gain can be different , from transistor model to another, even from J201 to J201, as we all know JFETs in general suffer from lack of fabrication consistency,and thats one of the reasons companies stop producing them. I recomend using a multi-turn varianble resistor in the drain, and bias the JFET to the loudest or prefered point. Also some times the source to ground resistor will need to the exchanged to have more gain and match the J201.

Also its possible to choose th SMD version of the J201(MMBFJ201), but it will require redesigning the PCB. Its possible to simply etch a small adapter that will allow using it on a thru hole board. This solution is also good for adapting JFETs with different pin outs than the J201 to the PCB that will use J201s.


Pozdrawiam
M.

[Seljer]

Yes, therethe same just in an SMD package.

Which are not that scary to solder as you think! You just need to add some tweezers and flux to your toolkit

At this scale you heavily rely on the surface tension to get the solder to run to where you want it so with "larger" components like transistors its not as precise work as it appears to be

[joejoe226]

Ice9, Mth5044, SmallBear, M23Bomber, Seljer

Thanks for the info.  I'm not using a pre-made PCB, so I'll be ok with the SMD version.  I was bummed my local shop didn't have them, then checked online and found out the TO-92 versions weren't being made anymore.

Might have to go back and see if they have a relacement M23Bomber mentioned.

joejoe

[Ice-9]

Ice9, Mth5044, SmallBear, M23Bomber, Seljer

Thanks for the info.  I'm not using a pre-made PCB, so I'll be ok with the SMD version.  I was bummed my local shop didn't have them, then checked online and found out the TO-92 versions weren't being made anymore.

Might have to go back and see if they have a relacement M23Bomber mentioned.

joejoe

Joejoe, How many j201's do you need, if you are in the UK I can pass a couple on to you, I still have a big bag full of them that I bought some time ago. Also 2N5457 I have.

[M23Bomber]

JoeJoe pleasure to help, May I inquire you, what are you building?

But again remind you thatsome these replacements have diferent pin outs.

I also add that you will need to recalculate the source resistors to obtain the same gain.  I recomend reading a few tutorials about 

A nice thing about knowing all the replcement for the J201 N-JFET, is, we can use recombine them and obtain different sounding stompbox.

I built a Dr Boogie ,  and i swaped arround several transistors (J201 (WERE MATCHED),  MPF102 and 2SK117), swapped the source resistor,and I got a "better tone" out of it and with less noise but the same gain.

[mth5044]

Joejoe, How many j201's do you need, if you are in the UK I can pass a couple on to you, I still have a big bag full of them that I bought some time ago. Also 2N5457 I have.

A true gentleman and a scholar!

[bwanasonic]

I had seen a mention here somewhere that some of the currently available j201s (specifically from Tayda) are either counterfeit or just plain low gain. How much of a concern is this? I have only have maybe 1 dozen "vintage" j201s. Are the j201s I might get now anemic?

[Jdansti]

Possibly.  The safest thing would be to buy JFETs from a known good supplier such as Small Bear.

[Pojo]

The last batch of J201s I got from Tayda were all good, and actually every batch I've gotten from them so far. They list the brand as being National but when I get them they're labeled Fairchild. All test good and I sort them for Idss within a certain range so that I can keep drain/source resistors the same for certain circuits I use them for. Out of 45 I bought from my last batch, only 5 fell outside of the preferred range.

There is a thread from a year or so ago that someone got J201's from them that were out of spec and probably were less desirable fets relabeled as J201. Looks like they've got a better supplier now.

But ultimately, if you want to be sure you're getting something authentic, go with Small Bear.