Go Back   Home > Forums > >
Home Forums Rules Articles diyAudio Store Blogs Gallery Wiki Register Donations FAQ Calendar Search Today's Posts Mark Forums Read

Analogue Source Turntables, Tonearms, Cartridges, Phono Stages, Tuners, Tape Recorders, etc.

Simplistic NJFET RIAA
Simplistic NJFET RIAA
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 23rd April 2009, 08:01 PM   #1681
nicoch58 is offline nicoch58  Europe
diyAudio Member
 
Join Date: Oct 2004
variable voltage drop down to 8v, idss dipendent ,10ma to 7ma

% match max ? ie 7,6 -7,8 are ok?
  Reply With Quote
Old 23rd April 2009, 08:06 PM   #1682
Salas is offline Salas  Greece
diyAudio Chief Moderator
 
Salas's Avatar
 
Join Date: Oct 2002
Location: Athens-Greece
Simplistic NJFET RIAA
I guess you measure voltage across some resistor so to extract IDSS current information. Use simpler and see. Yes, 7.6-7.8 not great matching is OK. It is not audio, its regulator.
Attached Images
File Type: png transistor_matching_jfet_idss.png (2.7 KB, 1158 views)
  Reply With Quote
Old 23rd April 2009, 08:13 PM   #1683
nicoch58 is offline nicoch58  Europe
diyAudio Member
 
Join Date: Oct 2004
probabile my stupid problem are only dmm battery , I just remenber without dmm in series ,and analog tester on v ,I dont see any drop !!!!

I will repor later, thanks a lot as always
  Reply With Quote
Old 23rd April 2009, 09:33 PM   #1684
nicoch58 is offline nicoch58  Europe
diyAudio Member
 
Join Date: Oct 2004
now work but I don't know why !!!
MiniReg problem...
  Reply With Quote
Old 24th April 2009, 03:44 AM   #1685
iko is offline iko  Canada
diyAudio Moderator
 
iko's Avatar
 
Join Date: May 2008
Location: Toronto
Simplistic NJFET RIAA
I didn't really understand the problem, but could it be sudden increase in current that causes voltage drops at those points? Also, if any parts get too hot, some of the current passing properties change quite a bit.
  Reply With Quote
Old 24th April 2009, 04:31 PM   #1686
nicoch58 is offline nicoch58  Europe
diyAudio Member
 
Join Date: Oct 2004
match done not so lucky
How can be the idss difference from channel ?

A----
k6.70-k6.70

k6.84-k6.91

b----
j7.72-k7.77

j7.90-k7.90

c----- but can be better for audio
j7.91-k7.90

j8.02-k8.02

d--- but losting the up combo for audio
k8.00-k8.02

k8.08-k8.09

e----- if idss is not too higth this are the better
k8.26-k8.27

j8.38-k8.37

with one ?
  Reply With Quote
Old 24th April 2009, 05:36 PM   #1687
Salas is offline Salas  Greece
diyAudio Chief Moderator
 
Salas's Avatar
 
Join Date: Oct 2002
Location: Athens-Greece
Simplistic NJFET RIAA
All will work. Your choice.
  Reply With Quote
Old 24th April 2009, 07:31 PM   #1688
nicoch58 is offline nicoch58  Europe
diyAudio Member
 
Join Date: Oct 2004
thanks , the same for R6 mod ?

a--- for r6 mod

e--- for Q5
  Reply With Quote
Old 24th April 2009, 08:07 PM   #1689
Salas is offline Salas  Greece
diyAudio Chief Moderator
 
Salas's Avatar
 
Join Date: Oct 2002
Location: Athens-Greece
Simplistic NJFET RIAA
Yes, good choices. Remember that R6 mod at this voltage you use is going to stress the BJT if not mini sinked.
  Reply With Quote
Old 24th April 2009, 08:24 PM   #1690
nicoch58 is offline nicoch58  Europe
diyAudio Member
 
Join Date: Oct 2004
just for fun or crazy

how mix for channel balance a-- and e-- jfet ?

ie: lower a-- idss for Q5 with higth e-- idss for R6mod
  Reply With Quote

Reply


Simplistic NJFET RIAAHide 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

Forum Jump


New To Site? Need Help?

All times are GMT. The time now is 11:58 AM.


Search Engine Optimisation provided by DragonByte SEO (Pro) - vBulletin Mods & Addons Copyright © 2017 DragonByte Technologies Ltd.
Resources saved on this page: MySQL 15.79%
vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2017 DragonByte Technologies Ltd.
Copyright ©1999-2017 diyAudio
Wiki