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

Pass Labs This forum is dedicated to Pass Labs discussion.

F5Turbo Illustrated Build Guide
F5Turbo Illustrated Build Guide
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 September 2018, 08:40 PM   #461
Zen Mod is online now Zen Mod  Serbia
Official Court Jester
diyAudio Member
 
Zen Mod's Avatar
 
Join Date: Jan 2003
Location: ancient Batsch , behind Iron Curtain
F5Turbo Illustrated Build Guide
for 28V5 rail (and you'll get something as Vac x1.25 , when PSU is loaded ) , use 15K up to rail , 10K down to GND

remember that you don't need making heaters of cascode bias net resistors ......... so no need for so low value as you suggested
__________________
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 11th September 2018, 08:49 PM   #462
kpsthakur is offline kpsthakur  India
diyAudio Member
 
Join Date: Sep 2016
Location: Delhi
Quote:
Originally Posted by Zen Mod View Post
for 28V5 rail (and you'll get something as Vac x1.25 , when PSU is loaded ) , use 15K up to rail , 10K down to GND

remember that you don't need making heaters of cascode bias net resistors ......... so no need for so low value as you suggested
O o forgot the current part... thanks Zen, will work on these values
  Reply With Quote
Old 12th September 2018, 05:24 PM   #463
kpsthakur is offline kpsthakur  India
diyAudio Member
 
Join Date: Sep 2016
Location: Delhi
Quote:
Originally Posted by Zen Mod View Post
for 28V5 rail (and you'll get something as Vac x1.25 , when PSU is loaded ) , use 15K up to rail , 10K down to GND

remember that you don't need making heaters of cascode bias net resistors ......... so no need for so low value as you suggested
Hi Zen, how much difference will it make if i keep both the resistances 10K, since the potential divider will just half the input voltage, in my case around ~14 V, guess that should work just fine
  Reply With Quote
Old 12th September 2018, 05:54 PM   #464
Zen Mod is online now Zen Mod  Serbia
Official Court Jester
diyAudio Member
 
Zen Mod's Avatar
 
Join Date: Jan 2003
Location: ancient Batsch , behind Iron Curtain
F5Turbo Illustrated Build Guide
yes , even if I like them slightly cooler
__________________
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 12th September 2018, 06:03 PM   #465
kpsthakur is offline kpsthakur  India
diyAudio Member
 
Join Date: Sep 2016
Location: Delhi
Quote:
Originally Posted by Zen Mod View Post
yes , even if I like them slightly cooler
So 15K is final...cooler, and splits the rail into half
  Reply With Quote
Old 12th September 2018, 06:14 PM   #466
Zen Mod is online now Zen Mod  Serbia
Official Court Jester
diyAudio Member
 
Zen Mod's Avatar
 
Join Date: Jan 2003
Location: ancient Batsch , behind Iron Curtain
F5Turbo Illustrated Build Guide
I meant - cooler JFets
__________________
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 September 2018, 03:44 AM   #467
sangram is offline sangram  India
diyAudio Member
 
Join Date: Sep 2002
Location: India
The Toshiba JFETs operate at lower noise when the Vds is lowered below 12V.

15k/10k combo would be absolutely perfect at ~28.5V rail, I would run them a little lower actually maybe 18k/10k.
  Reply With Quote
Old 13th September 2018, 05:25 AM   #468
kpsthakur is offline kpsthakur  India
diyAudio Member
 
Join Date: Sep 2016
Location: Delhi
Got it sir
  Reply With Quote
Old Yesterday, 07:19 PM   #469
esprit is offline esprit  Europe
diyAudio Member
 
Join Date: Mar 2010
Location: Lancashire
Well there is something I am just not getting !!!. as I still cannot get a logical result from the formula =

rail volt /(R26+R28)*R28= cascode voltage

please what is *R28

(my rails are 34.5)
  Reply With Quote
Old Yesterday, 07:22 PM   #470
6L6 is offline 6L6  United States
diyAudio Moderator
 
6L6's Avatar
 
Join Date: Oct 2010
Location: Denver, Colorado
F5Turbo Illustrated Build Guide
Click the image to open in full size.

There is one error in this schematic - R26 should be 10K

Original documentation here -

http://www.firstwatt.com/pdf/art_f5_turbo.pdf

Last edited by 6L6; Yesterday at 07:24 PM.
  Reply With Quote

Reply


F5Turbo Illustrated Build GuideHide 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

Similar Threads
Thread Thread Starter Forum Replies Last Post
Aleph J illustrated build guide 6L6 Pass Labs 2868 Yesterday 02:31 PM
ACA illustrated build guide 6L6 Pass Labs 145 21st September 2018 05:09 PM
diyAudio Power Supply Circuit Board v3 illustrated build guide 6L6 Power Supplies 698 18th September 2018 08:33 PM
An illustrated guide to building an F5 6L6 Pass Labs 1009 26th August 2018 06:23 PM
Illustrated guide to the 4U deluxe Chassis 6L6 Pass Labs 3 16th November 2013 04:32 PM


New To Site? Need Help?

All times are GMT. The time now is 05:57 AM.


Search Engine Optimisation provided by DragonByte SEO (Pro) - vBulletin Mods & Addons Copyright © 2018 DragonByte Technologies Ltd.
Resources saved on this page: MySQL 15.00%
vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2018 DragonByte Technologies Ltd.
Copyright ©1999-2018 diyAudio
Wiki