Replacement For Toshiba 2SK170/2SJ74

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#521
franzm said:
Hybrid pairs. Sometimes called Super G.
Click to expand...
What is the most common colloquial term for one half of the circuit ?
I know only the terms "Sziklai-Darlington" or CFP-Darlington (current feedback pair).
This seems to be me the most interesting approach for replace this jFET's from Toshiba, so as several other obsolete jFET's from Toshiba, NEC and Hitachi like 2SK369, 2SK389, 2SJ109, 2SK117 etc - particularly for new amplifier projects - go to
Sziklai pair - 1fet+1bjt.
Sziklai jfet input MC pre pre
Jfet Sziklai Single ended
Ing Electronica: CIRCUIT SPLINTERS
http://conocimientosbjt.blogspot.com/2010/07/circuit-splinters.html
https://sound-au.com/articles/followers.html#s6 (fig. 12)
Simple discrete Sziklai pre
Sziklai jfet input MC pre pre
Substitude for 2SJ109/2SJ74 wanted
F6 Amplifier (#1061, page 107)
for any inspirations.

This is a very long thread - therefore an overview (table of contents) of the most interesting postings:

Differences and Consequences by replacement of not obsolete versions)
#520, page 52: no replacements without disadvantages
#52, page 6: replacement disadvantages
#449, page 45: J113 disadvantages to 2SK170
#134+135, page 14: replace by MOSFET's ZVN/ZVP
#497+500, page 50: 2SK170BL = 2SK209GR
https://pdf1.alldatasheet.com/datasheet-pdf/view/30602/TOSHIBA/2SK209.html
#373+374, page 38: sziklai darlington (compound darlington) as replacement
#47, page 5: P-Ch version for BF862
#4, page 1: replacement 2SJ74
#34, page 4: replacements for MC head amp - go also to
https://www.onsemi.com/pub/Collateral/AN-6602.pdfJP.pdf

Genuine Parts vs. Fakes
#198, page 20: features of fakes resp. counterfeits
#20+112, page 2+12: seller of genuine parts
#316, page 32: counterfeits with internal die from other types
#290#291, page 30: image from outline with features in detail, not to find on fakes/counterfeits
#512-515, page 52: small tolerances within charges
#492, page 50: counterfeits simitar to J113/J176 (onsemi)
https://www.onsemi.com/pub/Collateral/J175-D.PDF
https://www.onsemi.com/pub/Collateral/MMBFJ113-D.PDF
https://pdf1.alldatasheet.com/datasheet-pdf/view/213179/TOSHIBA/2SK170.html
https://pdf1.alldatasheet.com/datasheet-pdf/view/30559/TOSHIBA/2SJ74.html

Matching Hints
#367, page 37: matching instructions
#124+126, page 13: special companies for matching
#210, page 21: image Tektronix set up 577+177 transistor analyzer/curve tracer

Various
#427, page 43: Toshiba Small Signal Applications Transistor Databook 1983
#211, page 22: overview various jFET's

B1 JFET alternatives list
NJFETs for Source Follower Applications
 
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#526
If you want/need/crave/... the real thing, you can still get them at a cost.
I ordered a small batch at Weiliang last April, they seem to be legit, but as usual with this seller, the same sex matching is spectacular, the opposite sex matching is... better than no matching. I also tested them with a 33R source resistor: a bit better, but not much.
Sadly, they almost double their price since.
 

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#528
Thanks, but no project nor fund. A while ago, I was looking for the opposite sex 2SK146, but now I have enough of them. But keep on shouting, maybe someone will hear you. Or send a PM to John Curl, maybe that'll motivate him to do a reissue of the CTC/Vendetta.
 
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