FS: PreAmp with Complimentary JFET Diff input & JFET ouput

USAcircuits · 15th June 2011, 02:09 AM

Hi folks,

I recently built a preamp with complimentary JFET input pairs and JFET output stages.
It produces very low distortion and renders an elegant and sophisticated sound typical of JFETs.
The project started with MicroCap simulation and was perfected with elaborate tweaking.

63308-C sch.pdf

PCB layout was done with Eagle 11.

63308-C pcb.pdf

Item will soon be available.

Regards,
US Audio Circuits

askii2 · 15th June 2011, 03:54 AM

usacircuits.com appears to have been suspended for some reason.

USAcircuits · 15th June 2011, 04:23 AM

My website was attacked by hacker the other day.

The webmaster has contacted the web hosting company.

Hope it will be fixed in a few days.

Thanks,
US Audio Circuits

USAcircuits · 15th June 2011, 12:29 PM

Correction :

The PCB layout software should be Eagle 5 v11.

Regards,
US Audio Circuits

SY · 15th June 2011, 12:46 PM

I'm moving this over to Vendors' since it is clearly a commercial offering.

EUVL · 15th June 2011, 12:50 PM

Pure coincidence, no doubt !!

I hope Erno will forgive me in this particular case for uploading his schematics, which was published at his website.

Patrick

(copyrighted drawing removed by moderators)

janneman · 15th June 2011, 01:36 PM

Quote:

Originally Posted by USAcircuits

Hi folks,

I recently built a preamp with complimentary JFET input pairs and JFET output stages.
It produces very low distortion and renders an elegant and sophisticated sound typical of JFETs.
The project started with MicroCap simulation and was perfected with elaborate tweaking.

Regards,
US Audio Circuits

Can you show us some sim results please?

jan didden

kevinkr · 15th June 2011, 04:31 PM

Quote:

Originally Posted by EUVL

Pure coincidence, no doubt !!

I hope Erno will forgive me in this particular case for uploading his schematics, which was published at his website.

Patrick

I've never seen this design, and I arrived at something very, very similar quite independently a very long time ago. I would proceed cautiously with this allegation. Everything I see here is prior art, and the proposed design actually differs in several key respects - I'll leave that to you to figure out.

barmanekm · 15th June 2011, 05:11 PM

I have built I/V and LineAmplifier full cascoded versions with small changes to the circuits allowing of extra cascode biasings in case proper devices are not found. So far I was able to startup I/V in passive mode. Because of the reasons above I will not post a detailed circuits but can post schematics without a values, and simulation results if anyone is interested.

USAcircuits · 15th June 2011, 08:19 PM

Janneman,

The final MicroCap simulation shows the following result :

63308-C 1KHz.jpg

Regards,
US Audio Circuits

15th June 2011, 02:09 AM	#1
USAcircuits diyAudio Member Join Date: Mar 2011 Location: East Coast	FS: PreAmp with Complimentary JFET Diff input & JFET ouput Hi folks, I recently built a preamp with complimentary JFET input pairs and JFET output stages. It produces very low distortion and renders an elegant and sophisticated sound typical of JFETs. The project started with MicroCap simulation and was perfected with elaborate tweaking. 63308-C sch.pdf PCB layout was done with Eagle 11. 63308-C pcb.pdf Item will soon be available. Regards, US Audio Circuits

15th June 2011, 12:46 PM	#5
SY diyAudio Moderator Join Date: Oct 2002 Location: Austin, TX Blog Entries: 1	I'm moving this over to Vendors' since it is clearly a commercial offering. __________________ “Listening to records is like ****ing a picture of Brigitte Bardot.” - Sergiu Celibidache

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15th June 2011, 03:54 AM	#2
askii2 diyAudio Member Join Date: May 2011 Location: Pune	usacircuits.com appears to have been suspended for some reason.

15th June 2011, 04:23 AM	#3
USAcircuits diyAudio Member Join Date: Mar 2011 Location: East Coast	My website was attacked by hacker the other day. The webmaster has contacted the web hosting company. Hope it will be fixed in a few days. Thanks, US Audio Circuits

15th June 2011, 12:29 PM	#4
USAcircuits diyAudio Member Join Date: Mar 2011 Location: East Coast	Correction : The PCB layout software should be Eagle 5 v11. Regards, US Audio Circuits

15th June 2011, 12:50 PM	#6
EUVL diyAudio Member Join Date: Oct 2003	Pure coincidence, no doubt !! I hope Erno will forgive me in this particular case for uploading his schematics, which was published at his website. Patrick (copyrighted drawing removed by moderators)

15th June 2011, 05:11 PM	#9
barmanekm diyAudio Member Join Date: Nov 2009 Location: Kraków	I have built I/V and LineAmplifier full cascoded versions with small changes to the circuits allowing of extra cascode biasings in case proper devices are not found. So far I was able to startup I/V in passive mode. Because of the reasons above I will not post a detailed circuits but can post schematics without a values, and simulation results if anyone is interested.

15th June 2011, 08:19 PM	#10
USAcircuits diyAudio Member Join Date: Mar 2011 Location: East Coast	Janneman, The final MicroCap simulation shows the following result : 63308-C 1KHz.jpg Regards, US Audio Circuits

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