Peppermill - J201 alternatives?

[ACS]

Hey all, am breadboarding up a Peppermill at the moment - but can't for the life of me find a J201 at any of our local stores here in Australia.  I thought they were common as muck; obviously not...

Anyways, what can I use as an alternative for this?  The notes at runoffgroove specificially say not to use a MPF102 or 2n3819...

Thanks
Aidan

[dukie]

Hey all, am breadboarding up a Peppermill at the moment - but can't for the life of me find a J201 at any of out local stores here in Australia.  I thought they were common as muck; obviously not...

Anyways, what can I use as an alternative for this?  The notes at runoffgroove specificially say not to use a MPF102 or 2n3819...

Thanks
Aidan

Hey Aidan try using 2SK117Y or 2SK30AY, both have average 1,2ma while J201 have 0,64ma drain current that means the overall gain will slightly differ. I've been using them in my BSIAB, Vetzer Valve and other JFET circuits I had build and it work just fine.

Cheers!

[ACS]

Thanks dukie - these are both MOSFETS aren't they?  Will they drop in as a replacement for the JFET?

[chicago_mike]

Also I believe the 2N5457. note the 2Sk117 might have a differing pinout.

[dukie]

Thanks dukie - these are both MOSFETS aren't they?  Will they drop in as a replacement for the JFET?

Nope, 2SK117Y & 2SK30AY are N Channel JFETs. You can find their datasheets in here2SK117.PDF , 2SK30.PDF , look for note on ldss classifications for JFET indentification marking series usually at the end of the JFET TO92 casing to determinate drain current that affect gain. Example, 2SK30 have 4 ldss class : 2SK30R have ldss 0,30-0,75ma, 2SK30O have 0.60-1.40ma, 2SK30Y have 1.20-3.00ma and 2SK30GR have 2.60-650ma. So you can find ldss that match J201's drain current that is 0.64ma(average).

Btw 2N5457 have ldss 1.96-4.11ma so it has a lower gain compare to J201. Use the Vetzer Valve Calculator for more accurate measurement.

Cheers!

[aron]

The store link above has J201.

[ACS]

Thanks Aron, unfortunately I'm pretty well stocked up for everything else at the moment, so can't justify a shipment all the way to Aus just for a couple of J201's!!  Next time I'm placing an order though, I'll definitely be getting some...

So, can't get the above mentioned either... Man, I really hate our local stores sometimes...

What I can get is an MPF106 (a.k.a. 2N5485) - this has a ldss of 1-5ma, so seems still lower gain than the J201, reckon this is likely to work OK?