Searching for an special JFET

roender · 13th May 2008, 12:51 PM

Where can I find an N-jfet with high transconductance, low noise, zero tempco at 2..10mA which will be part of LTP in an amplifier without glogal NFB?

john curl · 13th May 2008, 02:31 PM

I think you are asking for the almost impossible. Hi Gm does not easily give zero tempco, as you have to have a turnoff bias of about .8V, unless you start with really high Idss, which Toshiba (usually the highest Gm fets) doesn't have easily available.

CBS240 · 13th May 2008, 07:34 PM

Parallel J-fet's?

roender · 13th May 2008, 08:18 PM

Parallel devices? Very hard to match them on the same TC and Idss.
Maybe 2sk364V? ... but it seems to be unobtainable

roender · 14th May 2008, 07:07 AM

Opinions about 2sk364?
Where can I find some V grade?

PMA · 14th May 2008, 07:35 AM

You might buy a Marantz CD player with HDAM modules and take it out of the PCB. Mine is full of them, but I am enjoying its sound

.

roender · 14th May 2008, 07:57 AM

Quote:

Originally posted by PMA
You might buy a Marantz CD player with HDAM modules ... mine is full of them.

V grade? ... how many?
Thank you Pavel

PMA · 14th May 2008, 08:24 AM

Mihai, I am not sure if V grade. 2pcs per HDAM. Mine has 4 HDAMs.

Zen Mod · 14th May 2008, 08:47 AM

dunno is it helpfull

Bonsai · 14th May 2008, 08:51 AM

I can see precisely why these Marantz CD players sound grainy, have a harsh top end, constricted sound stage and a flat, undynamic overall sound, leading to listener fatigue after an hour or so.

They are using feedback.

13th May 2008, 12:51 PM	#1
roender diyAudio Member Join Date: Sep 2006	Searching for an special JFET Where can I find an N-jfet with high transconductance, low noise, zero tempco at 2..10mA which will be part of LTP in an amplifier without glogal NFB?

13th May 2008, 07:34 PM	#3
CBS240 diyAudio Member Join Date: Aug 2005 Location: K-town	Parallel J-fet's? __________________ All the trouble I've ever been in started out as fun......

14th May 2008, 08:51 AM	#10
Bonsai diyAudio Member Join Date: Aug 2006 Location: Taipei, Taiwan	I can see precisely why these Marantz CD players sound grainy, have a harsh top end, constricted sound stage and a flat, undynamic overall sound, leading to listener fatigue after an hour or so. They are using feedback. __________________ bonsai http://www.hifisonix.com/

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13th May 2008, 02:31 PM	#2
john curl diyAudio Member Join Date: Jul 2003 Location: berkeley ca	I think you are asking for the almost impossible. Hi Gm does not easily give zero tempco, as you have to have a turnoff bias of about .8V, unless you start with really high Idss, which Toshiba (usually the highest Gm fets) doesn't have easily available.

14th May 2008, 07:07 AM	#5
roender diyAudio Member Join Date: Sep 2006	Opinions about 2sk364? Where can I find some V grade?

14th May 2008, 07:35 AM	#6
PMA diyAudio Member Join Date: Apr 2002 Location: Prague, Kitakyushu, Fukuoka	You might buy a Marantz CD player with HDAM modules and take it out of the PCB. Mine is full of them, but I am enjoying its sound .

14th May 2008, 08:24 AM	#8
PMA diyAudio Member Join Date: Apr 2002 Location: Prague, Kitakyushu, Fukuoka	Mihai, I am not sure if V grade. 2pcs per HDAM. Mine has 4 HDAMs.

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