Ordered from punkydawgs Thurs, received Sat with a nice surprise sticky note. Lucky me!
BK
Cool!
Getting more parts for Pass amplifier builds? Don't you have enough built already?
But with such fine instruments, when can you say enough is enough? Becomes a case of more the merrier!
Last edited:
Cool!
Getting more parts for Pass amplifier builds? Don't you have enough built already?
But with such fine instruments, when can you say enough is enough?
In my mental dictionary some words are simply undefined. Enough = ???
BK
In my mental dictionary some words are simply undefined. Enough = ???
BK
Ok, new slogan "Enough is Nothing"...
Ordered from punkydawgs Thurs, received Sat with a nice surprise sticky note. Lucky me!
BK
Have you tested the jfets to make sure they are genuine? I'm considering getting a few matched quads from same seller
Have you tested the jfets to make sure they are genuine? I'm considering getting a few matched quads from same seller
Not tested yet, but this is one of a very small handful of trusted suppliers these days. Punkydawgs is bona-fide in both authenticity and matching care. Buy with confidence.
BK
Not tested yet, but this is one of a very small handful of trusted suppliers these days. Punkydawgs is bona-fide in both authenticity and matching care. Buy with confidence.
BK
Thank you.
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
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
In my mental dictionary some words are simply undefined. Enough = ???
BK
Enough = when you are at the limit of existing physical laws and you are unable to break them.
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
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
EUVL has posted a lot of information on getting the gm to match.
Yes indeed, it would be nice to summarize it here, as it is spread around the forum and difficult to find even using the search button
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
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
- Home
- Amplifiers
- Pass Labs
- Replacement For Toshiba 2SK170/2SJ74