Can I use the 2N5484 jfet diff pair in an audio amplifier front end?

carpenter · 25th March 2009, 12:09 AM

Hi guy,

I've been searching for alternative jfets, in case the 2SK170 becomes scarce--and for the shear fun of trying something new--and because I'm a tightwad on a budget. Ok, the last item should have probably been first in line.

I tried simming with a replacement from the SIMetrix library: 2N5484 was the first in line, so I gave it a go. I had to reduce the current, but it seems to sim nicely.

Anyone ever try this approach?

EUVL · 25th March 2009, 05:43 AM

Factor of 10 less gain, and noisy below 1kHz. Even above 1kHz is factor of 2-3.

Patrick

carpenter · 25th March 2009, 09:31 AM

Thank you very much, Patrick.

Is there a suitable replacement for the 2SK170? I'm willing to double up components.

nelsonvandal · 25th March 2009, 01:11 PM

I find SK170 so cheap I buy 100 at a time, match them closely for LTP use, and the rest I use as current sources/sinks.

SK170 (and SJ74) is in no way perfect, so I think it's interesting to hear of alternatives, so please report your findings.

coloradosound · 25th March 2009, 02:04 PM

You may check this thread:
Group Buy: Linear Systems LSK389 / LSK170 JFETs (i.e. Toshiba 2sk389/2sk170 subs)

Magura · 25th March 2009, 03:44 PM

Quote:

Originally posted by carpenter

Is there a suitable replacement for the 2SK170? I'm willing to double up components.

2SK369

Magura

carpenter · 25th March 2009, 03:46 PM

I've been scouring over my folder of "Choky" stuff. I reexamined the pumpkin (got to build that someday) and noticed he's using the J309.

That, of course, gave me the proper search word for DIY Audio. Within seconds, I had a long list of posts to read. It seems the J309 and it's J310 sibling are making more than one owner happy.

Off to Mouser I went. They have the J310 going for the ridiculous price of $37.00 for 500 pcs. I'm going to give it a go. I can match transistors and build amps until the moon falls from the sky at that rate.

carpenter · 25th March 2009, 03:47 PM

Magura's a funny guy....

Magura · 25th March 2009, 04:45 PM

Quote:

Originally posted by carpenter
Magura's a funny guy....

But really, how many would you like ?

Magura

EUVL · 25th March 2009, 05:15 PM

> Is there a suitable replacement for the 2SK170? I'm willing to double up components.

http://www.diyaudio.com/forums/showt...43#post1774443

Patrick

25th March 2009, 12:09 AM	#1
carpenter Paper mache horn fabricator diyAudio Member Join Date: Mar 2002 Location: Oregon City, Oregon	Can I use the 2N5484 jfet diff pair in an audio amplifier front end? Hi guy, I've been searching for alternative jfets, in case the 2SK170 becomes scarce--and for the shear fun of trying something new--and because I'm a tightwad on a budget. Ok, the last item should have probably been first in line. I tried simming with a replacement from the SIMetrix library: 2N5484 was the first in line, so I gave it a go. I had to reduce the current, but it seems to sim nicely. Anyone ever try this approach? __________________ I enjoy audio so much that I constructed a web site. I share my ideas at: www.inlowsound.com

25th March 2009, 09:31 AM	#3
carpenter Paper mache horn fabricator diyAudio Member Join Date: Mar 2002 Location: Oregon City, Oregon	Thank you very much, Patrick. Is there a suitable replacement for the 2SK170? I'm willing to double up components. __________________ I enjoy audio so much that I constructed a web site. I share my ideas at: www.inlowsound.com

25th March 2009, 03:46 PM	#7
carpenter Paper mache horn fabricator diyAudio Member Join Date: Mar 2002 Location: Oregon City, Oregon	I've been scouring over my folder of "Choky" stuff. I reexamined the pumpkin (got to build that someday) and noticed he's using the J309. That, of course, gave me the proper search word for DIY Audio. Within seconds, I had a long list of posts to read. It seems the J309 and it's J310 sibling are making more than one owner happy. Off to Mouser I went. They have the J310 going for the ridiculous price of $37.00 for 500 pcs. I'm going to give it a go. I can match transistors and build amps until the moon falls from the sky at that rate. __________________ I enjoy audio so much that I constructed a web site. I share my ideas at: www.inlowsound.com

25th March 2009, 03:47 PM	#8
carpenter Paper mache horn fabricator diyAudio Member Join Date: Mar 2002 Location: Oregon City, Oregon	Magura's a funny guy.... __________________ I enjoy audio so much that I constructed a web site. I share my ideas at: www.inlowsound.com

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25th March 2009, 05:43 AM	#2
EUVL diyAudio Member Join Date: Oct 2003	Factor of 10 less gain, and noisy below 1kHz. Even above 1kHz is factor of 2-3. Patrick

25th March 2009, 01:11 PM	#4
nelsonvandal diyAudio Member Join Date: Nov 2006	I find SK170 so cheap I buy 100 at a time, match them closely for LTP use, and the rest I use as current sources/sinks. SK170 (and SJ74) is in no way perfect, so I think it's interesting to hear of alternatives, so please report your findings.

25th March 2009, 02:04 PM	#5
coloradosound diyAudio Member Join Date: Nov 2005 Location: colorado	You may check this thread: Group Buy: Linear Systems LSK389 / LSK170 JFETs (i.e. Toshiba 2sk389/2sk170 subs)

25th March 2009, 05:15 PM	#10
EUVL diyAudio Member Join Date: Oct 2003	> Is there a suitable replacement for the 2SK170? I'm willing to double up components. http://www.diyaudio.com/forums/showt...43#post1774443 Patrick

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