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Old 15th June 2011, 05:36 PM   #12871
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Quote:
Originally Posted by EUVL View Post
Scott,

What I would really be interested to know, is whether the 2SK370 has the same die, or a smaller one ?

Unfortunately I do not have any 370's, else I would have sent you one. But Nelson has tons, and maybe he would sacrifice one for scientific curiosity ??




Patrick
I will need to do more as a group, it was harder than you think because we sell nothing in this package there was no jig. I'm not permitted to do the jet of fuming nitric that they use for this so I called in a favor.
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Old 15th June 2011, 09:08 PM   #12872
wayne is offline wayne  United States
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If you need some 2SK370 let me know. We are using them up and going to the stash of 2SK170.
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Old 15th June 2011, 09:33 PM   #12873
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Quote:
Originally Posted by scott wurcer View Post
Here is a genuine 2SK170, lots of tiny FET's in parallel
Cool. So they don't do that just with MOSFETs?

What about bipolars?

se
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Old 15th June 2011, 10:12 PM   #12874
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Originally Posted by SY View Post
"Ceci n'est pas un 2SK170."
The guys pulled the leads off but usually things still work after this! Could you explain the mechanism by which the nitric acid does not attack the circuit.
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Old 15th June 2011, 10:14 PM   #12875
Blues is offline Blues  United States
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Ayre K-5xeMP and Parasound Halo JC 2 on page 3 here...Ayre K-5xe<SUP>MP</SUP> line preamplifier | Stereophile.com
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Old 15th June 2011, 10:21 PM   #12876
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Default Not SY... but here's the reason

Quote:
Originally Posted by scott wurcer View Post
The guys pulled the leads off but usually things still work after this! Could you explain the mechanism by which the nitric acid does not attack the circuit.
unless there is copper or nickel somewhere, gold is immune, aluminum, chromium, niobium,etc. is passivated, silicon non-reactive, etc...

strong oxidizers CAN be your friend...

Used to make metal jets for streaming RFNO and UDMH... <<- rocket propellant... gotta be the right stuff or you get BFRC

Click the image to open in full size.

John L.
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Last edited by auplater; 15th June 2011 at 10:42 PM.
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Old 15th June 2011, 11:55 PM   #12877
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Btw for those who are struggling with the meaning of BFRC it is NOT the "British Flat Roofing Council" as first thought but NASAspeak for "Big Fr*gging Red Cloud".
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Old 16th June 2011, 12:00 AM   #12878
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Kind of interesting, isn't Charles Hansen and I, 'at each others throats' in serious competition, AND good colleagues to each other, as well. '-)
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Old 16th June 2011, 12:26 AM   #12879
SY is offline SY  United States
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What Auplater said. Hit it with some aqua regia and watch the chip turn into a Fizzies tablet.
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Old 16th June 2011, 01:02 PM   #12880
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Joshua - hope your 2SJ74 jfets aren't the same high idss BL ones I bought from an Israeli seller on eBay . The surface of his jets are dull where the original device's label has been etched off chemically and reprinted as J74BL's and the seller claims they are mislabeled as the idss is really 17 to 19 ma (the high idss switching jfets mentioned by others). The visual clue is the etched surface of the devices face, not glossy like real ones. electrically testing them is of course the real answer, but as soon you see them look for a glossy sheen to the face, if it's flat and rough run away .
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