I just picked up a pass kit in the swap meet a while ago and the toshiba jfets were included...
here are some pics.
the 2sk170 look normal but the other 2 have absolutely no writing on them. has anyone seen these?
Can I assume they are the j counterparts of the 170's?
are they real?
Apparently they came from someone named Spencer?
Thanks in advance!!
here are some pics.
the 2sk170 look normal but the other 2 have absolutely no writing on them. has anyone seen these?
Can I assume they are the j counterparts of the 170's?
are they real?
Apparently they came from someone named Spencer?
Thanks in advance!!
Attachments
If they indeed came from Spencer, they are good....I have bought many sets from him, never had one with no writing...were not packaged like that either, never had stickers like that on them. Who knows?
Russellc
Russellc
They don't look like they've been sanded, it looks like it was cast that way. There's also some weird sort of adhesive, transparent looking plastic on the back of it. I'm just asking because I have never seen a Toshiba J Fett without marking on it. Could have been some sort of OEM thing?. I have no reason not to trust the person I bought it from....
The Toshiba parts have a very small untinned section as the leads leave the package.
The packages look very different from each other, but we need to see more of it to know for sure.
Far as I know there are only two variations of the K170/J74 pair and none look like that, but there may be more.
The packages look very different from each other, but we need to see more of it to know for sure.
Far as I know there are only two variations of the K170/J74 pair and none look like that, but there may be more.
If they came from Spencer then there is nothing to worry about.
There were some dual jfets (for example 2sj75) that are two jfets (ex. 2sj74) matched
at the factory and placed in a metal package. I don't believe those parts were marked
(the markings are on the metal case) and I recall people were taking the jfets out of
the metal cases to use as singles.
There were some dual jfets (for example 2sj75) that are two jfets (ex. 2sj74) matched
at the factory and placed in a metal package. I don't believe those parts were marked
(the markings are on the metal case) and I recall people were taking the jfets out of
the metal cases to use as singles.
Seems they come from liubincalvin as a split from 2SJ75. Read Selling Zhou Fang’s remaining stocks including some very rare Toshiba transistors for more detail.
Those would be cut pieces.
Typically made by cutting the package from the middle and removing the metal section around the package.
I never knew those existed.
Typically made by cutting the package from the middle and removing the metal section around the package.
I never knew those existed.
Okay, I think I see now. The aluminum package has to glued into it facing each other. That's why the face doesn't look Cut, and it looks like residue of some sort of glue on the back of it. So does that mean I can use these without wearing? I don't want to build this vfet amp and have it make Magic Smoke on the very first try.....
You can do basic Idss measurements to allay your concerns. It'll make you sleep
better and it's also a good exercise.
better and it's also a good exercise.
I have 2sj74 (?) without markings.
I bought them (as matched) at this forum allegedly coming from yet another forum member.
As I did not trust my own Idss measurements (there were a tad off from what the vendor told me, but still perfectly fine and matched) I asked at the alleged source whether he new what the Idss of my copies were. They came with some numbers on stickers attached to them so he was willing to help me as he keeps a record. Unfortunately the stickers had different color so he quickly replied that these jfets were not from him.
I haven't done any more measurements on my copies. They seem to work fine.
In fact they play in the best head amp I have built so far (it is the 4th but not the last one)
I still hope I haven't been taken the advantage of. Maybe the vendor has just forgotten/messed up something.
The reason I am writing this is to say that it is reassuring that there are unmarked 2sk170/2sj74 out there.
I bought them (as matched) at this forum allegedly coming from yet another forum member.
As I did not trust my own Idss measurements (there were a tad off from what the vendor told me, but still perfectly fine and matched) I asked at the alleged source whether he new what the Idss of my copies were. They came with some numbers on stickers attached to them so he was willing to help me as he keeps a record. Unfortunately the stickers had different color so he quickly replied that these jfets were not from him.
I haven't done any more measurements on my copies. They seem to work fine.
In fact they play in the best head amp I have built so far (it is the 4th but not the last one)
I still hope I haven't been taken the advantage of. Maybe the vendor has just forgotten/messed up something.
The reason I am writing this is to say that it is reassuring that there are unmarked 2sk170/2sj74 out there.
Hah!
I looked again at the pics attached at the beginning of this thread and they looked pretty much like mine.
In fact I traced back my quad 2sk170/2sj74 in the spreadsheet in the link provided in post #7!!!!! And my Idss match what is in the spreadsheet!
Thank you guys!
I looked again at the pics attached at the beginning of this thread and they looked pretty much like mine.
In fact I traced back my quad 2sk170/2sj74 in the spreadsheet in the link provided in post #7!!!!! And my Idss match what is in the spreadsheet!
Thank you guys!