low noise JFET, how about this one - diyAudio
Go Back   Home > Forums > Amplifiers > Solid State

Solid State Talk all about solid state amplification.

Please consider donating to help us continue to serve you.

Ads on/off / Custom Title / More PMs / More album space / Advanced printing & mass image saving
Reply
 
Thread Tools Search this Thread
Old 28th September 2005, 09:52 AM   #1
diyAudio Member
 
Join Date: Jul 2001
Location: The Netherlands
Default low noise JFET, how about this one

Hi all,

if been looking for a low noise solution for a THD meter I'm building.. how about this one: the NE23383B ?

Wouldn't this be a nice device to work with?

how about the 1/f noise? I cann't find info on that..

How do you guys feel about using such a device in a pearl-type of application?


regards,
Thijs
Attached Files
File Type: pdf ne23383.pdf (22.2 KB, 567 views)
  Reply With Quote
Old 28th September 2005, 10:31 AM   #2
Electrons are yellow and more is better!
diyAudio Member
 
peranders's Avatar
 
Join Date: Apr 2002
Location: Göteborg, Sweden
Blog Entries: 4
The question is how the noise is in the audio band
__________________
/Per-Anders (my first name) or P-A as my friends call me
Super Regulator SSR03 Group buy
  Reply With Quote
Old 28th September 2005, 10:44 AM   #3
diyAudio Member
 
runebivrin's Avatar
 
Join Date: Jul 2003
Location: Huddinge, Sweden
Send a message via MSN to runebivrin
Not to rain on your parade, but this is a low voltage RF device. While there's no reason to believe it wouldn't work for audio, something tells me it's not what the manufacturer has in mind...

Unless, of course, you're planning on measuring the THD of you micro wave oven?

Rune
__________________
Do wizards use spell checkers?
  Reply With Quote
Old 28th September 2005, 10:50 AM   #4
Electrons are yellow and more is better!
diyAudio Member
 
peranders's Avatar
 
Join Date: Apr 2002
Location: Göteborg, Sweden
Blog Entries: 4
Have you seen Tangent's low noise preamp for purposes like yours?

http://tangentsoft.net/elec/meas-preamp/

If you are dealing with measurements it may be an idea to not overdo things. First state needed noise level based on facts. I have a hard time to believe that you'll need less the 1 uV in resolution.

If 1uV is enough <4 nV/Hz is enough.
__________________
/Per-Anders (my first name) or P-A as my friends call me
Super Regulator SSR03 Group buy
  Reply With Quote
Old 28th September 2005, 11:33 AM   #5
diyAudio Member
 
jackinnj's Avatar
 
Join Date: Apr 2002
Location: Llanddewi Brefi, NJ
I chose the Analog Devices SSM2019 -- available as an SOIC8 or SO20W outline for my noise measurement preamp -- is is fully differential and gain is set quite simply with one resistor. The device did not add any noise to a simple loop from the source of my Boonton 1120 analyzer (which has balanced outputs) to the single ended input. The threshold of the Boonton is about 0.0007% You could probable do one even better with some of the newer IN amps from TI.

You will find that when you get down to the microvolts and nanovolts of measurement layout becomes critical -- further -- just moving the cables creates a triboelectric effect which will influence measurements. Keilthly Instruments sells special cables just for these purposes.

For your amusement read some of the measurement articles written by Bob Pease of National Semiconductor -- how to measure picos and femtos.
  Reply With Quote
Old 28th September 2005, 12:11 PM   #6
diyAudio Member
 
Join Date: Jul 2001
Location: The Netherlands
Thanks for the suggestions!

Indeed it seems like a RF device, but what do you think: should it be low noise down to the 1KHz region? 10Hz even?

I was dreaming about building a < 0.5nV/sqrt(HZ) amplifier.. should I stick to the 2SK170? Or BTJ, given that the Rsource is < 1KOhm...

I have a article decribing a 0.33nV/sqrtHZ JFET amplifier using 9 sony 2sk152 transistor in paralellel ... actually .. i wanna beat this thing


thanks!
Thijs
  Reply With Quote
Old 28th September 2005, 01:13 PM   #7
diyAudio Member
 
jacco vermeulen's Avatar
 
Join Date: Oct 2004
Location: At the sea front, Rotterdam or Curaçao
Send a message via Yahoo to jacco vermeulen
Feel free to post the JFet article, Thijs.
  Reply With Quote
Old 28th September 2005, 01:17 PM   #8
diyAudio Member
 
jackinnj's Avatar
 
Join Date: Apr 2002
Location: Llanddewi Brefi, NJ
you mean:
G M Gutt et al 1991 Supercond. Sci. Technol. 4 633-636
"An ultralow noise amplifier for superconductive detectors"

there are a lot of good low noise preamp/amp articles to be found in the superconducting and space arenas -- some of the devices which are now just finding their way to the outer regions of our solar system are based on 1990's technology.

take a look at this:
http://ewiserver.npl.washington.edu/...NCD_Preamp.pdf
  Reply With Quote
Old 28th September 2005, 03:18 PM   #9
diyAudio Member
 
Join Date: Jul 2001
Location: The Netherlands
Yes that's the one ! ... just browsing all kinds of journals here at the university, I allready stumpled on a few articles that get me thinking that 1nV/sqrtHZ is not the limit...
  Reply With Quote
Old 28th September 2005, 03:30 PM   #10
diyAudio Member
 
Join Date: Jul 2001
Location: The Netherlands
Nice one Jackinnj... thasnk! somewhere betwen 0.467 and 0.67 nV/sqrtHZ... but again at high frequencies only...
  Reply With Quote

Reply


Hide this!Advertise here!
Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
SWM Seeking JFET /w low noise + high Vp aletheian Solid State 3 11th July 2007 12:18 PM
Low noise dual JFET pair rtarbell Parts 4 17th March 2006 10:11 PM
Ultra low noise dual jfet Pjotr Parts 7 6th December 2003 02:10 PM
Interesting app note on JFET noise TheFettler Solid State 8 19th September 2002 02:02 PM


New To Site? Need Help?

All times are GMT. The time now is 12:00 PM.


vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2014 DragonByte Technologies Ltd.
Copyright ©1999-2014 diyAudio

Content Relevant URLs by vBSEO 3.3.2