Nice sounding JFET recos...

Tieftoener · 21st March 2003, 05:03 PM

Hey all,

In Jocko's I-V stage thread, he mentioned that he would use a JFETT follower at the output stage as a buffer....

Quote:

......but I would add a buffer for a number of reasons. A simple JFET follower works well here.

I'm looking for some suggestions on nice sounding JFETs... got any?

I picked up a couple VHF JFETs at Rat Shack last night to play with something... (the part number escapes me

) but I doubt they're of good caliber. Also picked up a pair of IRF510 mosfets to play with. Thought maybe I'd run them in a cascode configuration...

Again, looking for suggestions on a nice Class A preamp output buffer for Jocko's (and Tschrama's) I-V stages

Thanks -

Fred Dieckmann · 21st March 2003, 06:55 PM

Jocko uses paralleled 2SK170s as follower biased by a BJT current source. I have one of his DACs and a couple of Buffer boards for CD players he designed. I use the Borbely Jfet version of the White cathode follower. McCormack audio uses a complementary 2SK170 2SJ74 pair follower in their buffered passive preamps. They sound very good.

Great jfet circuits:

http://www.borbelyaudio.com/ae599bor.pdf
http://www.borbelyaudio.com/ae699bor.pdf
http://www.borbelyaudio.com/borb502.pdf

http://www.forsselltech.com/schemati...et%20Opamp.PDF

Toshiba Jfet data sheets:

http://katalogi.iele.polsl.gliwice.p...d.php?id=70389
http://katalogi.iele.polsl.gliwice.p...d.php?id=70372

Where to buy Toshiba jfets:

http://www.ceitron.com/
http://www.mcmelectronics.com/

Did I leave anything out?

Tieftoener · 21st March 2003, 07:30 PM

Holy cow!

Thanks Fred!

With the PCM63 in my Denon DCM370, PMD100 HDCD Digital filter, the removal of those horrible muting transistors, removal of a really poopy electrolytic cap for DC removal, and the swap of an old JRC opamp with my OPA2134's, I was in total heaven this week while I again reevaluated my entire collection of music. Now, I'll get to do it all over again after making a REAL I-V stage... Muuuuwaaahaaahaahaahaaaaaaaaaaa!!

mlloyd1 · 22nd March 2003, 12:16 AM

I've seen the NEC (I think

) 2SK163 used a buffer and preamp front end in RIAA and line level commericial equipment. This device is still available cheaply from the places Fred mentions

Unfortunately however, I have yet to find a datasheet for this device. So, I can't say it's better or worse than 2SK170 until I fire 'em up

Fred didn't leave anything out. I've tried some of those circuits over the years and they sound great!

Gee Fred, how much hard drive space DO you have ?

Quote:

Originally posted by Fred Dieckmann
...Did I leave anything out?

prh · 23rd March 2003, 04:10 AM

Fred,

Thanks so much for those JFET links!

This is some of the most useful info I've gleaned from the forum.

Much appreciated!

Paul.

21st March 2003, 06:55 PM	#2
Fred Dieckmann diyAudio Retiree Join Date: Oct 2002 Location: Spain or the pueblo of Los Angeles	jfet followers Jocko uses paralleled 2SK170s as follower biased by a BJT current source. I have one of his DACs and a couple of Buffer boards for CD players he designed. I use the Borbely Jfet version of the White cathode follower. McCormack audio uses a complementary 2SK170 2SJ74 pair follower in their buffered passive preamps. They sound very good. Great jfet circuits: http://www.borbelyaudio.com/ae599bor.pdf http://www.borbelyaudio.com/ae699bor.pdf http://www.borbelyaudio.com/borb502.pdf http://www.forsselltech.com/schemati...et%20Opamp.PDF Toshiba Jfet data sheets: http://katalogi.iele.polsl.gliwice.p...d.php?id=70389 http://katalogi.iele.polsl.gliwice.p...d.php?id=70372 Where to buy Toshiba jfets: http://www.ceitron.com/ http://www.mcmelectronics.com/ Did I leave anything out?

21st March 2003, 07:30 PM	#3
Tieftoener diyAudio Member Join Date: Nov 2002 Location: Coastal AL	Holy cow! Thanks Fred! With the PCM63 in my Denon DCM370, PMD100 HDCD Digital filter, the removal of those horrible muting transistors, removal of a really poopy electrolytic cap for DC removal, and the swap of an old JRC opamp with my OPA2134's, I was in total heaven this week while I again reevaluated my entire collection of music. Now, I'll get to do it all over again after making a REAL I-V stage... Muuuuwaaahaaahaahaahaaaaaaaaaaa!! __________________ Tieftoener -- You're ears can sense a movement in air that causes your eardrum to move less than 1/10th of the diameter of a Hydrogen atom! Don't abuse the one of the most amazing organs your Creator gave you!

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23rd March 2003, 04:10 AM	#5
prh diyAudio Member Join Date: Sep 2002 Location: Brisbane. Australia	Fred, Thanks so much for those JFET links! This is some of the most useful info I've gleaned from the forum. Much appreciated! Paul.

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