Jfet Bosoz? - Page 3 - diyAudio
Go Back   Home > Forums > Amplifiers > Pass Labs

Pass Labs This forum is dedicated to Pass Labs discussion.

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 11th March 2007, 08:16 PM   #21
The one and only
 
Nelson Pass's Avatar
 
Join Date: Mar 2001
Quote:
Originally posted by dw8083
If this Jfet BOSOZ was connected only to an Aleph30, are the output coupling caps necessary? It would be great to eliminate them if possible.
The + input is direct coupled, and usually the - input has a
capacitor to give low offset. I would keep the coupling caps,
but you could then eliminate the cap on the A30

  Reply With Quote
Old 11th March 2007, 10:05 PM   #22
diyAudio Member
 
Join Date: Nov 2006
Quote:
with output followers
if you want to "gild the lily"
Were you thinking of something like seven watt output followers?
  Reply With Quote
Old 11th March 2007, 10:33 PM   #23
The one and only
 
Nelson Pass's Avatar
 
Join Date: Mar 2001
I believe that would qualify.

  Reply With Quote
Old 13th March 2007, 09:24 PM   #24
diyAudio Member
 
hifimaker's Avatar
 
Join Date: Oct 2003
Location: San Jose
Here's a first start at a design. Any thoughts? I'd like to get some feedback before building it. Source followers could be added.

-David
Attached Images
File Type: jpg jfetbosoz.jpg (51.9 KB, 2116 views)
  Reply With Quote
Old 13th March 2007, 09:35 PM   #25
Zen Mod is offline Zen Mod  Serbia
diyAudio Member
 
Zen Mod's Avatar
 
Join Date: Jan 2003
Location: ancient Batsch , behind Iron Curtain
Quote:
Originally posted by dw8083
Here's a first start at a design. Any thoughts? I'd like to get some feedback before building it. Source followers could be added.

-David

increase current (change J type,or use two or use another type of CCS);

after that -be careful with dissipation; decrease PS voltage ,if needed

edit:
R7 and R8 are in 10x magnitude bigger for my liking.........susy effect is smaller with them,degeneration is greater.........


for vinyl (next post,edit after):

Q2 and cousin are CCSes,cascodes,what you like?

__________________
my Papa is smarter than your Nelson !
clean thread; Cook Book;PSM LS Cook Book;Baby DiyA ;Mighty ZM's Bloggg;Papatreasure;Papa...© by Mighty ZM
  Reply With Quote
Old 13th March 2007, 09:40 PM   #26
diyAudio Member
 
Onvinyl's Avatar
 
Join Date: Aug 2002
Location: Germany
OK folks,
I'll be the fool of the day and the one who asks the question that no one dares to ask...

What is the function of Q2 and how does it work?

Rüdiger
__________________
"I can feel what's going on inside a piece of electronic equipment. I have a sense that I know what's going on inside the transistors." Robert Moog
  Reply With Quote
Old 13th March 2007, 10:12 PM   #27
diyAudio Member
 
hifimaker's Avatar
 
Join Date: Oct 2003
Location: San Jose
Thanks Choky for the insight.

This version has a second J511, lower voltage, and adjustments to R5-8. I would appreciate help in verifying the design and specifically in selecting values for R5-8. I think the values maybe a bit low.

Thank you,

-David
Attached Images
File Type: jpg jfetbosoz.jpg (52.7 KB, 1374 views)
  Reply With Quote
Old 13th March 2007, 10:24 PM   #28
Zen Mod is offline Zen Mod  Serbia
diyAudio Member
 
Zen Mod's Avatar
 
Join Date: Jan 2003
Location: ancient Batsch , behind Iron Curtain
Quote:
Originally posted by dw8083
Thanks Choky for the insight.

This version has a second J511, lower voltage, and adjustments to R5-8. I would appreciate help in verifying the design and specifically in selecting values for R5-8. I think the values maybe a bit low.

Thank you,

-David
try like this

you must adjust R5 and R6 to catch J511's 4,7mA through each side

connection of J511 corrected and few other things

but,I usually make a mess............
edit:

move both 100K resistors to 2k2/22k node (not before 2k2 but after,ditto on gate)
Attached Images
File Type: jpg jfetbosoz.jpg (43.3 KB, 1417 views)
__________________
my Papa is smarter than your Nelson !
clean thread; Cook Book;PSM LS Cook Book;Baby DiyA ;Mighty ZM's Bloggg;Papatreasure;Papa...© by Mighty ZM
  Reply With Quote
Old 13th March 2007, 10:42 PM   #29
diyAudio Member
 
hifimaker's Avatar
 
Join Date: Oct 2003
Location: San Jose
Thanks Choky, I missed the wire between R7 & R8, it's now added. I'm still wondering if R5 & R6 are on the small side?

Here's the updated schematic.

-David

EDIT: Moved C1 & C2 back, outside of R2 & R4
Attached Images
File Type: jpg jfetbosoz.jpg (53.8 KB, 1265 views)
  Reply With Quote
Old 13th March 2007, 10:59 PM   #30
Zen Mod is offline Zen Mod  Serbia
diyAudio Member
 
Zen Mod's Avatar
 
Join Date: Jan 2003
Location: ancient Batsch , behind Iron Curtain
Quote:
Originally posted by dw8083
Thanks Choky, I missed the wire between R7 & R8, it's now added. I'm still wondering if R5 & R6 are on the small side?

Here's the updated schematic.

-David
if your intention was to make CCS-es with two upper LSKs (hehehe) ,then you must look in data or test them ..........I don't know from top of my head what's Ugs for 4,7mA.............off course-you must match them,so you'll know then what resistors to choose

besides that-for later -you can add followers on output,naturally with overall feedback connected all around

edit:
if you are lazy for testing and matching,you can always send me handful of little critters and I'll do that for ya
__________________
my Papa is smarter than your Nelson !
clean thread; Cook Book;PSM LS Cook Book;Baby DiyA ;Mighty ZM's Bloggg;Papatreasure;Papa...© by Mighty ZM
  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
Krazy JFET-cascoded Pass BOSOZ jh6you Pass Labs 60 17th March 2006 01:19 AM
Poll! What do you use in your X-BOSOZ or BOSOZ for Volume Control and Input Selector? promitheus Pass Labs 87 19th February 2006 04:15 PM
Krazy PSU for JFET cascode BOSOZ jh6you Pass Labs 24 14th February 2006 04:00 PM
Cascoded jfet in X-BOSOZ?? Magura Pass Labs 44 31st January 2006 09:00 PM
Can I replace BF245C JFET with J201 JFET? bigmike216 Parts 2 7th December 2005 07:50 AM


New To Site? Need Help?

All times are GMT. The time now is 07:25 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