another UnDIY'er thread
Looks like the real problem here is, this thread seems to be one of the "not so DIY Audio" pointers thread, where those with commercial interests and products can probe each others IP, sort of like writing a patent such that the examiner will approve it as having legs, but witholding enough info to truly protect the trade secret that makes it unique (and hopefully profitable).
All those DIY'ers not in the industry posting her, raise your hands...
Looks like the real problem here is, this thread seems to be one of the "not so DIY Audio" pointers thread, where those with commercial interests and products can probe each others IP, sort of like writing a patent such that the examiner will approve it as having legs, but witholding enough info to truly protect the trade secret that makes it unique (and hopefully profitable).
All those DIY'ers not in the industry posting her, raise your hands...
Me
You don't count! As you give useful advice, that actually has value to those of us less experienced
The same goes for Scott, he also can't claim any status in that clan.
Magura
Unlikely.
They typically have double the 2SK170 transconductance and this can't be only a gaussian tail. Most likely, a larger area chip of the same cell layout.
That's would be real close to a 2sk269, but I bet that the capacitances also is higher than for an average LSK170c?
Magura
Any suggestions?
I was under the impression that the 2sk369 was about the best I could get for the purpose.
Magura
Unfortunately some of these might be equally obsolete, I was thinking of things like the old E410 series from Siliconix which might be available from Linear Systems. The noise gets down to 3nV or so and the C's are only 1-3pF. By linearity I mean gos. The input Vgs-Id transfer function is the same square law for all FET's.
EDIT- Hand matched 2SK222's would give you a good go too. 10mS at 1mA and only 8-10pF.
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Try the Hoya progressive lens. Expensive, but worth every penny. No swimming effect. Closest in similarity to single vision lenses I've ever had.
Looks like the real problem here is, this thread seems to be one of the "not so DIY Audio" pointers thread, where those with commercial interests and products can probe each others IP, sort of like writing a patent such that the examiner will approve it as having legs, but witholding enough info to truly protect the trade secret that makes it unique (and hopefully profitable).
All those DIY'ers not in the industry posting her, raise your hands...
Don't quite get the drift here, I certainly am not in the audio industry. The non-DIY aspect to me is "if you can't get X unobtainable part there is no point in proceeding".
Well, what I have to say is this: I predict that IF you parallel two 2sk389's with an Idss at 8ma, you will have more input capacitance, that one 2sk389 with an Idss of 16ma. Geometry rules, not Idss. You know, twice the surface area in the device's effective geometry gives more input capacitance. Idss is controlled by another variable, does anyone know what it is?
Apply a square wave via a series resistor. Measure rise time. I'll probably screw the pooch on the constant (away from my references), but I think the capacitance is the time for the square wave leading edge to reach 63% of its max value divided by the series resistance.
Hmm, they both are about as obsolete as they come. At least the usual suspects didn't have any.
Something tells me that I should just be happy about the stock of 2sk369bl.
Magura
John, now look, those who knows don't bother playing your little games, those who don't know, also don't bother playing your little games.
So, guess what?
Either explain what you claim to know, or don't, but really, get a hold of yourself.
Nobody bothers playing your little games.
What can I say? It's a damned shame. You're having a bad day.
Magura
FYI - Data sheets unfortunately use the concept of Ciss and Crss. The extrapolated zero bias capacitances and formula for C vs V (usually ~1/3 power law) is the way SPICE does it and I find this preferable. In this case Cgs and Cgd are usually about the same value. The main point is that you can compute the correct value for each in your circuit.
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