I am informed by www.circuitdiy.com (Acronman) that they do have more
of the parts. I have purchased from them before and I regard them as
reliable.
of the parts. I have purchased from them before and I regard them as
reliable.
hmmm
Not sure what's going on - I got a bunch of them, graded KD-33, and the bias points are nothng like that curves posted. Despite being more used to triodes I know silicon aint that repeatable (at least until selected and graded!), but for I get, for example:
Vgs = -9V
Vds = -8V, Ids -1.29A
Vgs = -18V
Vds = -14.9V, Ids -1.29A
I've looked at 2 devices and they are pretty close.
I.e. gate more negative than the drain? Is this remotely correct?! I suppose it might be consistent with a mu (dVds/dId) of <1 as measured....
thanks again,
cv
Not sure what's going on - I got a bunch of them, graded KD-33, and the bias points are nothng like that curves posted. Despite being more used to triodes I know silicon aint that repeatable (at least until selected and graded!), but for I get, for example:
Vgs = -9V
Vds = -8V, Ids -1.29A
Vgs = -18V
Vds = -14.9V, Ids -1.29A
I've looked at 2 devices and they are pretty close.
I.e. gate more negative than the drain? Is this remotely correct?! I suppose it might be consistent with a mu (dVds/dId) of <1 as measured....
thanks again,
cv
Hi Mike,
Completely understood and I appreciate the prompt reply, as ever. My immediate concern was that the devices not be defective; reading between the lines has provided some reassurance! And some ideas for hybrid circuitry....
Nelson - I suspect I may still be confused with P-channel (at least, until someone brings out some positronic triodes for me to play with)... drain positive with respect to source you say? Interesting... I shall return to the bench tomorrow.
Thanks again gentlemen,
Chris
Completely understood and I appreciate the prompt reply, as ever. My immediate concern was that the devices not be defective; reading between the lines has provided some reassurance! And some ideas for hybrid circuitry....
Nelson - I suspect I may still be confused with P-channel (at least, until someone brings out some positronic triodes for me to play with)... drain positive with respect to source you say? Interesting... I shall return to the bench tomorrow.
Thanks again gentlemen,
Chris
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"Lightbulb moment"
I have been correspondingly dim...
My error has been pointed out. I was thinking I didn't understand SITs, or they had to be applied weirdly, or my clip leads were jumbled, my supplies weren't floating... basically everything but the obvious resolution staring me in the face.
Occam and Sherlock are shaking their heads, muttering "2sk, 2sk, 2sk..." (with rather less grace than NP, who mentioned it only once)
Tea-bag - please ignore *all* my previous replies and look at Nelson's post - it's all in there, as usual - that way you won't blow any devices up. Or better yet, forgive my cryptic response and await the publication of Mike's articles!
Cheers,
cv
I have been correspondingly dim...
My error has been pointed out. I was thinking I didn't understand SITs, or they had to be applied weirdly, or my clip leads were jumbled, my supplies weren't floating... basically everything but the obvious resolution staring me in the face.
Occam and Sherlock are shaking their heads, muttering "2sk, 2sk, 2sk..." (with rather less grace than NP, who mentioned it only once)
Tea-bag - please ignore *all* my previous replies and look at Nelson's post - it's all in there, as usual - that way you won't blow any devices up. Or better yet, forgive my cryptic response and await the publication of Mike's articles!
Cheers,
cv
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Thanks Mike, back on my own two feet now
I took a few Vds/Id curves at Vgs = -2, -4 and -6V; the current was a fair bit lower than the published curves above, but I suspect that's due to the grade "33" devices I have, and qualitatively the curves look as I'd expect.
Can't recall where, but somewhere online was mentioned that the grades run from xx2-xx8, with higher numbers yielding more power; I took this to mean they will require more negative bias for the same current, so a wider voltage swing and more power is possible. Would seem consistent with my results.
My curves are a bit kinked up on high but I'm certain that's due to transconductance dropping as the things heat up - my curve tracer is a dual bench PSU with twiddly knobs...
I was expecting a high tempco from the published curves, given that the lines show some hysteresis, particularly on the 2SJ complementary device.
This has made me even more curious about the SIT-1 parts, as I recall SiC has a much lower tempco than Si - I suspect the absence of this signal modulation mechanism is an underrated feature of vacuum tubes in terms of sonics and may contribute in part to the excellence of the new amps.
Nonetheless, things are looking up for the 2SK82s - will eventually test some more devices and hopefully fire an amp up later this month.
Thanks again - and one more question if I may - *where* exactly will your articles be appearing?
Cheers,
cv
I took a few Vds/Id curves at Vgs = -2, -4 and -6V; the current was a fair bit lower than the published curves above, but I suspect that's due to the grade "33" devices I have, and qualitatively the curves look as I'd expect.
Can't recall where, but somewhere online was mentioned that the grades run from xx2-xx8, with higher numbers yielding more power; I took this to mean they will require more negative bias for the same current, so a wider voltage swing and more power is possible. Would seem consistent with my results.
My curves are a bit kinked up on high but I'm certain that's due to transconductance dropping as the things heat up - my curve tracer is a dual bench PSU with twiddly knobs...
I was expecting a high tempco from the published curves, given that the lines show some hysteresis, particularly on the 2SJ complementary device.
This has made me even more curious about the SIT-1 parts, as I recall SiC has a much lower tempco than Si - I suspect the absence of this signal modulation mechanism is an underrated feature of vacuum tubes in terms of sonics and may contribute in part to the excellence of the new amps.
Nonetheless, things are looking up for the 2SK82s - will eventually test some more devices and hopefully fire an amp up later this month.
Thanks again - and one more question if I may - *where* exactly will your articles be appearing?
Cheers,
cv
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