2SK30 - JFET or MOSFET? (Noob warning)

[thermionix]

So I built the Geofex JFET Vgsoff matcher.  But I don't have many JFETs on hand to sort through, just a few each of a few types.  Checking Tayda I was a little surprised at how expensive JFETs are, so I started looking for lots on Ebay, various types.

I'm not yet committed to building a Phase 90 or 45 at this point, but I'm using those circuits as a guide.  I read several threads about them here, and one recommended JFET sub seems to be the 2SK30.

Found some on Ebay from China for a good price, but they describe them as MOSFETs.  Google search brings up mixed results.

JFETs and MOSFETs are two different things, right?  Or is a 2SK30 both?  If it is a MOSFET, is that still a good sub in the Phase 90?

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Okay, secondary question.  I was testing some of the JFETs I have to make sure the tester I built worked.  Most were giving me "typical" results, like 1.6 or 2.4V...seems the tester is working.

But then I grabbed four NOS NTE458s I have, and the test results ranged from .03 to .05V.  Is that right?  Pretty radically different.  I'm sure I had the pinout correct, it's printed on the NTE package.

[bluebunny]

JFETs are expensive now because they are obsolete and becoming rare.  The 2SK30 is indeed a JFET, not a MOSFET.  The two are quite different and you can't generally sub one for the other.

[thermionix]

So, probably best to not buy from this seller...

http://www.ebay.com/itm/10pcs-2SK30A-GR-MOS-Field-Effect-Transistor-TO-92-/191548242371?hash=item2c992a39c3:g:l9QAAOSwrklVDOBG

The price seems nice though.

Seems the datasheet google results I was getting were of pages that had more than one type of transistor, so it looked like they were confirming MOSFET until I looked closer.  Like info for 2SK3069 was showing up instead.

Thanks for the reply.

[bluebunny]

You know what they say about "too good to be true"?      But for only two bucks, I'd be pretty tempted to give this a go.  Ya never know, ya might strike it lucky...

[EBK]

JFETs are expensive now because they are obsolete and becoming rare. 

Surface mount JFETs are still readily available and cheaper. Carefully tack some leads on or solder them directly to veroboard strips and you're good to go. I admit, it would be a much bigger pain in the butt to go through a matching process with a pile of those....

(Of course, my solution is simply to not build phasers  )

[duck_arse]

about your linked ad at the popular auction site - the part in the photo shows all the right stuff for a 2SK30A-GR, but seller then goes and blows it by claiming they are 2SK30A-Y. Y and GR are different "gain bukkets". I'd ignore his "mos" ref.

K30A is a valid search term. tayda have K117 for 0.20 out of stock which would have been adequate, so you could skip over to futurelec for a lookie - I can vouch for their K30A's, but everyone here will tell tales of woe about their speed of delivery and response.

see:
http://futurlec.com/TransMos2N.shtml

[thermionix]

JFETs are expensive now because they are obsolete and becoming rare. 

Surface mount JFETs are still readily available and cheaper. Carefully tack some leads on or solder them directly to veroboard strips and you're good to go. I admit, it would be a much bigger pain in the butt to go through a matching process with a pile of those....

Yeah screw that.

[EBK]

JFETs are expensive now because they are obsolete and becoming rare. 

Surface mount JFETs are still readily available and cheaper. Carefully tack some leads on or solder them directly to veroboard strips and you're good to go. I admit, it would be a much bigger pain in the butt to go through a matching process with a pile of those....

Yeah screw that.

Screw surface mount?

[thermionix]

Jscrew or MOSscrew?