Hi all there folks!
I'm restoring this amplifier which have a blown 2SK389
.
So i think maybe i can replace it with a good 2sk109 i have...
But the 2sk389 have a substrate pin which the 2sk109 has not...
Its safe to do this replacement and leave the substrate connection for the on the PCB open?
Im attaching a picture of the schematic showing the connection of this substrate pin, so anyone who can help me know what im talking about, if its safe to use the 2sk109 and leave alone the 220ohm resistor?
Thanks in advance
I'm restoring this amplifier which have a blown 2SK389
.
So i think maybe i can replace it with a good 2sk109 i have...
But the 2sk389 have a substrate pin which the 2sk109 has not...
Its safe to do this replacement and leave the substrate connection for the on the PCB open?
Im attaching a picture of the schematic showing the connection of this substrate pin, so anyone who can help me know what im talking about, if its safe to use the 2sk109 and leave alone the 220ohm resistor?
Thanks in advance
Attachments
you cannot substitute 109 for 389
The 109’ is P channel - the 389 is an N channel jfet
You can still get 389GR from diyaudio member
FS: Toshiba 2SK389 -GR, 2SA1349 -GR, 2SC3381 -GR
You can use matched pair of 2 sk170GR - must be matched pair
The 109’ is P channel - the 389 is an N channel jfet
You can still get 389GR from diyaudio member
FS: Toshiba 2SK389 -GR, 2SA1349 -GR, 2SC3381 -GR
You can use matched pair of 2 sk170GR - must be matched pair
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Attachments
Get the 389Gr, its not expensive, and it’s in Sweden
The 2sk109 I never saw before, you can’t tell from data sheet what it’s idss range is and its a single line package, it would difficult to mount where a 389 was, maybe not impossible , but not easy. Get the 389GR ( and a spare 1 or 2) while you still can.
Gr is the idss group, GR, BL, and V . You need to replace with same idss group if possible.
Maybe some Malbec in Puerto Madero
The 2sk109 I never saw before, you can’t tell from data sheet what it’s idss range is and its a single line package, it would difficult to mount where a 389 was, maybe not impossible , but not easy. Get the 389GR ( and a spare 1 or 2) while you still can.
Gr is the idss group, GR, BL, and V . You need to replace with same idss group if possible.
Maybe some Malbec in Puerto Madero
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Thanks but im in Argentina, that part would be here in 2 months maybe more, and i have the 2sk109 here with me so thats why im asking.
I looked at the pdfs and both seems N channel, but didnt know about IDSS and the substrate pin
99% of 389 designs never connecthe substrate, but this one does,
Idss you can read about here:
http://www.raylectronics.nl/pdfs/Audio_Electronics_JFETs.pdf
Idss you can read about here:
http://www.raylectronics.nl/pdfs/Audio_Electronics_JFETs.pdf
I measured idss using the circuit provided on the link
Measured half 2sk389 (just one of the two fets in the package was blown) and measured 6.10mA.
Did the same with the 2sk109 and measured 6.18mA so both are pretty close!
Measured half 2sk389 (just one of the two fets in the package was blown) and measured 6.10mA.
Did the same with the 2sk109 and measured 6.18mA so both are pretty close!
If the idss matches that closely your are very lucky. Even a few ma difference would probably be OK.
Can you fit the K109 into the K389 holes?
The 109 is a single in line package, while the 389 was a TO 71 pinout
Electrically it seems possible, but not all the same specs are available for the K109.
The data sheet for the 109 shows it used exactly in the same circuit position that Sony used it in your amp as an input differential pair, cascoded and with a current mirror..
You can try if you want but I can’t take responsibilty for it working or blowing up the amp.
There are others like Anatech, the diy moderator, he’s very helpfull, or John Curl who might advise, but the 2 sk109 is rare .I’ve never heard of it until now.
Me, i’d wait the 2 months in Mar del Plata for a new 389GR, Quilmes frio con dos empanada de carne por favor.
Can you fit the K109 into the K389 holes?
The 109 is a single in line package, while the 389 was a TO 71 pinout
Electrically it seems possible, but not all the same specs are available for the K109.
The data sheet for the 109 shows it used exactly in the same circuit position that Sony used it in your amp as an input differential pair, cascoded and with a current mirror..
You can try if you want but I can’t take responsibilty for it working or blowing up the amp.
There are others like Anatech, the diy moderator, he’s very helpfull, or John Curl who might advise, but the 2 sk109 is rare .I’ve never heard of it until now.
Me, i’d wait the 2 months in Mar del Plata for a new 389GR, Quilmes frio con dos empanada de carne por favor.
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