Fake or real 2SK2013?

I'm trying to determine if some 2SK2013s I have are genuine or not. The case looks good (although the placement of the 'Y' grade marking is suspect: I think it's usually under the '2').


(Pics of other real & fake 2SK2013s can be found here: https://www.diyaudio.com/forums/pass-labs/168040-f5-2sk2013-2sj313-25.html#post2658976)

I did some manual curve tracing with a couple of bench supplies. This is ID over VGS, with VDS fixed at 10V:


While the curve looks about right, note that it's offset to the right by about 1.8V. I know the curve in the datasheet is only representative, but would there be that much variation in VGS?

Thanks, guys. Nikko have been gracious in taking them back.

Quest is advertising them for something like 48c a piece, so I ordered a bunch (mostly for a laugh). Then again, if they turn out to be genuine I'll have a gold mine. ;)

I also found some at B&D, which I expect to be genuine. (Sadly they're sold out of 2SJ313.)
Hi Jeff,

My original Toshiba's all have the "Y" under the 2. Also the 0 has a break in it at the 12 and 6 o'clock positions.

As Dennis mentions, mine all test at around 1.9ish volts for Vgs.

Also the lettering is too bright, the originals were always dull and harder to read.

At least the supplier took them back.

Well, here's a surprise.

B&D (and punkydawgs) are my go-to sources for obsolete parts because you know you're getting the real thing. Neither is cheap. (The 2SK2013s from B&D cost me $18.59 each.)

Quest, on the other hand, make me nervous. I've ordered from them about 3 times and always gotten genuine parts, but I was pretty sure this time I wouldn't. No picture, and they were selling them for $1.41 a piece, and I had just returned some top-dollar counterfeits from Nikko.

But they were cheap, and I figured it was worth it to keep abreast of what the counterfeiters were doing.


Turns out they're real.





B&D part on left; Quest on right. (Suggested difference in size & reflectivity just down to camera angle.)


Both measure the same (Vgs in the 1.8V - 1.9V range, with similar curves).

And hey, how can you resist a classification of 'Y' followed by a '0u' date code?



  • various 2SK2013.JPG
    various 2SK2013.JPG
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Unable to pass up a deal like that, I ordered a bunch more from Quest, this time with 2SJ313 to go along with them.

And dang it if the 313s aren't real too.

I'd recommend these to others, but they're no longer showing stock. Either I bought them out, or they've taken them down to re-price them. :scratch2: