Simplistic NJFET RIAA - Page 856 - diyAudio
Go Back   Home > Forums > Source & Line > Analogue Source

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

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 19th November 2012, 08:05 PM   #8551
Doug R is offline Doug R  United States
diyAudio Member
 
Join Date: Oct 2007
Location: Indy
OK, so you're saying to lose the PS resistors to get back to about 38 Vin right?
I was initially worried about frying all the sandy things, so I didn't want voltage into the regulator to be too high.

I appreciate your evaluation from a distance. I have been so worried about measuring little things and not seeing the big picture of how much current I was drawing.

Efharistó Salas.

Doug
  Reply With Quote
Old 19th November 2012, 08:09 PM   #8552
Doug R is offline Doug R  United States
diyAudio Member
 
Join Date: Oct 2007
Location: Indy
One more thing:
I still want 38 Vin with a 60 mA (28 V/0.06 A = 466 ohm) load, right.

How do you put up with idiots like me?

Thanks.
  Reply With Quote
Old 19th November 2012, 08:11 PM   #8553
Salas is offline Salas  Greece
diyAudio Chief Moderator
 
Salas's Avatar
 
Join Date: Oct 2002
Location: Athens-Greece
Quote:
Originally Posted by Doug R View Post
OK, so you're saying to lose the PS resistors to get back to about 38 Vin right?

Doug
Right. First thing is we have enough Vin and from there we see next. But look on B & C points of thinking while you are at it. (#8548).
  Reply With Quote
Old 19th November 2012, 08:14 PM   #8554
Salas is offline Salas  Greece
diyAudio Chief Moderator
 
Salas's Avatar
 
Join Date: Oct 2002
Location: Athens-Greece
Quote:
Originally Posted by Doug R View Post
One more thing:
I still want 38 Vin with a 60 mA (28 V/0.06 A = 466 ohm) load, right.

How do you put up with idiots like me?

Thanks.
No worries, I do worse all the time myself.

When such reg works its CCS properly, then its output load changes nothing for its input draw. Its a current regulator wall between input and output sorta.
  Reply With Quote
Old 19th November 2012, 08:18 PM   #8555
Doug R is offline Doug R  United States
diyAudio Member
 
Join Date: Oct 2007
Location: Indy
OK Salas,
Here are the gridstoppers, 'cause to me gridstoppers are for TUBES, not sandy things.
I will move them to be right at the legs, and decouple raw supply with some film caps.
Doug
Attached Images
File Type: jpg Topside.jpg (65.2 KB, 112 views)
  Reply With Quote
Old 19th November 2012, 08:42 PM   #8556
Salas is offline Salas  Greece
diyAudio Chief Moderator
 
Salas's Avatar
 
Join Date: Oct 2002
Location: Athens-Greece
Doh before, good now if will be moved smack on gate pin. See them stoppers as sandy bridge without Intel I7 price tag crossing over to heater-less pentodes. That will sweeten this bitter pill somehow.
  Reply With Quote
Old 19th November 2012, 08:49 PM   #8557
Doug R is offline Doug R  United States
diyAudio Member
 
Join Date: Oct 2007
Location: Indy
Nah, unless they're round and made of glass, they are just three legged fuses to me.
Maybe I'll glue a 45 tube in there to make it look real.
I will post again tomorrow.
  Reply With Quote
Old 19th November 2012, 08:50 PM   #8558
Salas is offline Salas  Greece
diyAudio Chief Moderator
 
Salas's Avatar
 
Join Date: Oct 2002
Location: Athens-Greece
See ya then.
  Reply With Quote
Old 20th November 2012, 01:32 PM   #8559
Doug R is offline Doug R  United States
diyAudio Member
 
Join Date: Oct 2007
Location: Indy
Good Morning Salas!

Changed the raw PS. Bridge to 4 ohm R --- 100 uF Cap ---- 2H Choke----4700 uF Cap ------ 4 Ohm R ------4700 uF Cap, then to Reg

Initially this raised Vin to Reg up to 30 volts, so I replaced the 10 ohm R1 with 22 ohm to get load down. Vin went up to 47 volts,

Vin = 47 V
Vout = 3.5 V with 500 ohm load on reg and pot set at 1.5 kOhm
V across R1 now 1.8 V (1.8 V/22 Ohm = 82 mA)
V across R4 = 46 V
V across R5 = 0.62 V

Q1 G to S = 3.0 V
Q4 G to S = 3.3 V

Q3 B to E = 0.6 V
Q6 B to E = o.6 V
Q7 B to E = 0.7 V

Q2 G to D = 3.3 V
Q5 G to D = 0.7 V

What's next boss?
Thanks!
Doug
  Reply With Quote
Old 20th November 2012, 01:33 PM   #8560
Doug R is offline Doug R  United States
diyAudio Member
 
Join Date: Oct 2007
Location: Indy
Also, put CF gate stoppers in nest to Q1 and Q4 and added 0.1 uF cap across input terminals.
  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



New To Site? Need Help?

All times are GMT. The time now is 04:05 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