[alphaman]

I've come across several applications for these devices; and they seem especially desirable to audio based on modern pricing (ebay or Ali).
One interesting appl. is in line-level output stages of DACs and preamps (e.g. older Classe gear).

I think only Hitachi manuf'd them (correct me if I'm wrong).
The 2sj76 - 2sj79 (p-ch) seems especially elusive and can fetch a hefty sum (ebay) for new-old-stock or even used (extracted) units.
So is the demand justified?
And, in any case, are there other to-220 devices that can do the same thing as the "2s" Hitachi mosfets? They don't have to be avail or even cost-effective. Just that they are drop-in substitutes.

 

[alphaman]

It seems as if I should have looked a bit deeper, esp. the Ali listings.
And if the listings are correct, then the buying options are quite attractive.
That is, the two are sold as "matched' sets. E.g., 2sj76 / 2sk213 (pair) for about $3.00 plus s/h.
Not sure how they match them, unless they extracted them from, say, old scrap receivers, that had matched mosfets already ??????????

 

[justin w.]

be careful because those types of parts are very likely to be fakes

 

[alphaman]

be careful because those types of parts are very likely to be fakes

How does one “fake “ such devices?
Is it really worth faking such low-cost parts?
There is another issue that may affect the quality and integrity of these old, possibly extracted parts. Anyone care to guess what that might be?