Replacement For Toshiba 2SK170/2SJ74

Ordered from punkydawgs Thurs, received Sat with a nice surprise sticky note. Lucky me!


BK
 

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I bought 5 quads from punkydawgs.
Big thanks to Mr. Pass who told this seller is realiable.
The only big downside for me is a pricey international shipping.
I got this values of Idss Vgs measured by punkydawgs:

N 733 149
N 736 150
P 734 138
P 736 138

N 733 156
N 735 158
P 734 129
P 735 131

N 738 151
N 739 153
P 736 129
P 736 130

N 742 154
N 745 155
P 742 141
P 744 142

N 744 159
N 746 141
P 746 131
P 746 133
 
Reading around the forum that the 170/74 are not 100% complementary

If I am not mistaken you should use a 20% higher Idss for 74 and degenerate it with 5ohm more than the 170 to get them 100% complementary.

Can some one confirm or complement this?
The info is so spread on the forum that I can' retrieve any more, and it can be of interest for all
because it is then interesting to buy +20% matched pairs instead of equal idss
 
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If I am not mistaken you should use a 20% higher Idss for 74 and degenerate it with 5ohm more than the 170 to get them 100% complementary.

This is correct for the average FETs. In practice variation is quite big and to do the job well you will have to actually measure the FETs and find those where it works. But as I understand that is not your cup of tea as long as somebody else spoon feeds....

By the way, I did buy and test a couple of those Toshiba 2SJ74-GR you found at Reichelt.de and they are indeed fakes (way to low transconductance).
 
as I am starting in DIY audio, have a lot to learn and practice. Some spoon feed at the beginning is useful ;)

I only wanted confirmation that I understood correctly. +20% idss and +5r degeneration for 74 compared to the 170 in most of the cases. Still better than equal matched Idss
The only thing I would like to avoid is to buy many 170/74 to match and measure.

Thanks to all for your help (spoon feeding), and thanks for having tested the reichelt.de fakes