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 26th March 2009, 10:55 PM   #1481
Salas is offline Salas  Greece
diyAudio Chief Moderator
 
Salas's Avatar
 
Join Date: Oct 2002
Location: Athens-Greece
Simplistic NJFET RIAA
Will do proper AB now that it got well broken in. Planning in the next few days. Will post.
  Reply With Quote
Old 26th March 2009, 11:10 PM   #1482
Salas is offline Salas  Greece
diyAudio Chief Moderator
 
Salas's Avatar
 
Join Date: Oct 2002
Location: Athens-Greece
Simplistic NJFET RIAA
Quote:
Originally posted by RCruz
When you have time, please comment on the drawing... I must be sure there are now flaws this time.
I think that you got all JFETS facing the wrong way.
Attached Images
File Type: gif sk170.gif (7.2 KB, 464 views)
  Reply With Quote
Old 26th March 2009, 11:16 PM   #1483
Salas is offline Salas  Greece
diyAudio Chief Moderator
 
Salas's Avatar
 
Join Date: Oct 2002
Location: Athens-Greece
Simplistic NJFET RIAA
Unless you actually show the underside in the pdf.
  Reply With Quote
Old 27th March 2009, 02:26 PM   #1484
RCruz is offline RCruz  Switzerland
nhinstruments
diyAudio Member
 
RCruz's Avatar
 
Join Date: Sep 2006
Location: Wallis
Simplistic NJFET RIAA
Hi salas

I forgot to tell you this is the underside of the board.

Apart from that issue, do you agree with the overall schematic ?
__________________
RC
  Reply With Quote
Old 27th March 2009, 02:42 PM   #1485
Salas is offline Salas  Greece
diyAudio Chief Moderator
 
Salas's Avatar
 
Join Date: Oct 2002
Location: Athens-Greece
Simplistic NJFET RIAA
Yes it looks OK. I would make provision for an alternative general earthing point to star at C2 earth node too, just in case. Also try a 1k8 R20 on your current phono to see if it stabilizes easier.
  Reply With Quote
Old 27th March 2009, 04:19 PM   #1486
RCruz is offline RCruz  Switzerland
nhinstruments
diyAudio Member
 
RCruz's Avatar
 
Join Date: Sep 2006
Location: Wallis
Simplistic NJFET RIAA
Thank you Salas

Increasing R20 lowers voltage in Q5.... will it affect sound quality ?

What should I expect ?

Should I have more than 1 GND point ? my actual setup has one star gnd where all gnd´s go.
__________________
RC
  Reply With Quote
Old 27th March 2009, 04:29 PM   #1487
Salas is offline Salas  Greece
diyAudio Chief Moderator
 
Salas's Avatar
 
Join Date: Oct 2002
Location: Athens-Greece
Simplistic NJFET RIAA
I meant to have one point still, but different take off alternatives just in case. Regarding R20 I thought it may help you if there is less voltage across Q5 regarding the noises you get. Since nobody else ever got the noises, I don't know more. Its a proposed experiment. You will tell if it helps the noises you get during warm up or if it changes the sound. The current remains the same.
  Reply With Quote
Old 27th March 2009, 04:39 PM   #1488
RCruz is offline RCruz  Switzerland
nhinstruments
diyAudio Member
 
RCruz's Avatar
 
Join Date: Sep 2006
Location: Wallis
Simplistic NJFET RIAA
I believe noises come from bad solder joints... my pcb is now a real mess.... that is why I want to rebuild everything.

If nobody else reported any issues, maybe I should stick to your original design.

Another pertinent question:

I am now using 2K21 RC55Y Welwin 0,1% metal film for cart loading and really think this is the perfect value.

I would like to try Shinkoh in there but do not know if I need to change the value.

I would really apreciate your comment.

Ricardo
__________________
RC
  Reply With Quote
Old 27th March 2009, 05:04 PM   #1489
Salas is offline Salas  Greece
diyAudio Chief Moderator
 
Salas's Avatar
 
Join Date: Oct 2002
Location: Athens-Greece
Simplistic NJFET RIAA
Normally Shinkoh gives the most grain free and organic rendering there. But not heavy at the same time. I would keep the value. Only thing is that with Shinkoh you can normally go higher in value before you get some ''pinch'' as with other resistors.
  Reply With Quote
Old 27th March 2009, 06:49 PM   #1490
RCruz is offline RCruz  Switzerland
nhinstruments
diyAudio Member
 
RCruz's Avatar
 
Join Date: Sep 2006
Location: Wallis
Simplistic NJFET RIAA
Can you please suggest a good quality DMM ?

Myne is able to read capacitances but I always get lower values than indicated in the caps. (For instance, K72-6 0.047u reads 44.6nF)

ERO 620pF reads 599pF....

Mundorf 4.7uF MKP reads 4.4u ...

__________________
RC
  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 08:57 PM.


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