Semisouth JFET's: What are they good for?

Magura · 6th October 2009, 07:51 PM

As I've been trying to keep the Semisouth GB thread reasonably clean, I guess it's time to open a dedicated thread, for discussing what we can get out of those little fellas

So.......do your worst

Magura

Michael Rothacher · 6th October 2009, 08:02 PM

A Son of Zen (or some variant) could be fun.

Magura · 6th October 2009, 08:10 PM

Some iteration of the F3 could also be interesting.

Could be easy, as there are boards made already, and most around here, already have the PSU part.

Magura

ra7 · 6th October 2009, 09:20 PM

Can you pop these buggers directly into the circuits as they are?

Zen Mod · 6th October 2009, 10:20 PM

Quote:

Originally Posted by ra7

Can you pop these buggers directly into the circuits as they are?

yup , with few minor changes in some resistor values .......

Nelson Pass · 6th October 2009, 10:31 PM

They are pretty much drop in replacements for vertical
Mosfets. The bias voltage and thermal characteristics would
probably support replacements of Laterals as well.

audiotux · 11:36 PM

a Semisouth J-Fet Dao-Headphone Amp ?

slr 5000 · 6th October 2009, 11:53 PM

hi guys
im glad this thread has been started as i was not sure what to use mine for

what about replacing the irfp240 on a aleph 4 clone ?

is this doable and if so would i need the same amount ie 24

regards sheafer

Tea-Bag · 7th October 2009, 01:38 AM

Nelson's J2 circuit has elements of the Aleph-J and BA-1 from what I see.
Can't be too wrong to start somewhere around their. will ask cviller at BA-3 what's going on with those front end boards.

tinears02 · 7th October 2009, 10:36 AM

How prone are these Semisouth devices to oscillations compared to
say, a mosfet? MOS devices would typically need a couple of hundred ohms
right at the gate to stabilise them, are these required at these values?

TIA

6th October 2009, 07:51 PM	#1
Magura diyAudio Member Join Date: Oct 2003 Location: Denmark, Viborg	Semisouth JFET's: What are they good for? As I've been trying to keep the Semisouth GB thread reasonably clean, I guess it's time to open a dedicated thread, for discussing what we can get out of those little fellas So.......do your worst Magura __________________ Everything is possible....to do the impossible just takes a little while longer. www.class-a-labs.com

6th October 2009, 08:02 PM	#2
Michael Rothacher www.audiohobby.com diyAudio Member Join Date: May 2001 Blog Entries: 3	A Son of Zen (or some variant) could be fun. __________________ My Website, Projects, Sale Items

6th October 2009, 08:10 PM	#3
Magura diyAudio Member Join Date: Oct 2003 Location: Denmark, Viborg	Some iteration of the F3 could also be interesting. Could be easy, as there are boards made already, and most around here, already have the PSU part. Magura __________________ Everything is possible....to do the impossible just takes a little while longer. www.class-a-labs.com

6th October 2009, 11:33 PM	#7
audiotux diyAudio Member Join Date: Nov 2004 Location: Bruchsal/Germany	a Semisouth J-Fet Dao-Headphone Amp ? Last edited by audiotux; 6th October 2009 at 11:36 PM. Reason: Failure

7th October 2009, 01:38 AM	#9
Tea-Bag not politcally affiliated diyAudio Member Join Date: Feb 2006 Location: Kennebunk Blog Entries: 7	Nelson's J2 circuit has elements of the Aleph-J and BA-1 from what I see. Can't be too wrong to start somewhere around their. will ask cviller at BA-3 what's going on with those front end boards. __________________ Salas Boards 2013 #2 CLICK HERE \| F6 Covertible PCB GB Boards Available \|DCB1 boards and KITS available PM\|SemiSouth R125, R100, R100A Available CLICK HERE \|F5TC Boards Sign UP CLICK HERE


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6th October 2009, 09:20 PM	#4
ra7 diyAudio Member Join Date: Feb 2009 Blog Entries: 1	Can you pop these buggers directly into the circuits as they are?

6th October 2009, 10:31 PM	#6
Nelson Pass The one and only Join Date: Mar 2001	They are pretty much drop in replacements for vertical Mosfets. The bias voltage and thermal characteristics would probably support replacements of Laterals as well.

6th October 2009, 11:53 PM	#8
slr 5000 diyAudio Member Join Date: Oct 2007 Location: melbourne	hi guys im glad this thread has been started as i was not sure what to use mine for what about replacing the irfp240 on a aleph 4 clone ? is this doable and if so would i need the same amount ie 24 regards sheafer

7th October 2009, 10:36 AM	#10
tinears02 diyAudio Member Join Date: Sep 2003 Location: earth	stability issues ? How prone are these Semisouth devices to oscillations compared to say, a mosfet? MOS devices would typically need a couple of hundred ohms right at the gate to stabilise them, are these required at these values? TIA

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