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 30th October 2012, 11:16 PM   #151
NicMac is offline NicMac  Italy
diyAudio Member
 
NicMac's Avatar
 
Join Date: Feb 2009
Although I should allow you to enjoy your achievements I can't help to show where I am....
In blue the calculated Idss/Yfs of the 2SJ74 after 5R1 degeneration.
Attached Images
File Type: png 2SK170_2SJ74.png (48.8 KB, 538 views)
  Reply With Quote
Old 31st October 2012, 03:58 AM   #152
EUVL is offline EUVL  Europe
diyAudio Member
 
Join Date: Oct 2003
Nice figure.
Shows clearly that my guestimation 5R1 is near spot on !!!!




Patrick
__________________
xen-audio.com
  Reply With Quote
Old 31st October 2012, 08:07 AM   #153
NicMac is offline NicMac  Italy
diyAudio Member
 
NicMac's Avatar
 
Join Date: Feb 2009
Of course your 5R1 value was chosen for a reason like most things you do

For my FETs I actually find 5R6 and 6R2 to be a bit better. As computing cost little I in the end actually used 7 different Rdeg (4R3, 4R7, 5R1, 5R6, 6R2, 6R8 and 7R2) to generate a virtual set of 2723 degenerated 2SJ74's (see figure) and used these for matching. With those I obtained 42 NNNNPPPP-sets with 0.5% tolerance for both Idss and Yfs. This is a yield of about 43% for the 2SJ74.

Of course there is the downside that each 2SJ74 will need a different Rdeg. But as a DIY'er I can live with this minor logistic complication.

Obviously Oneclock has measured matches while mine are calculated and should to be verified experimentally. I nevertheless trust the practical validity of the equations some kind person provided me with

Where is that F5X Pre?

Cheers,

Nic

P.S. Note how increasing Rdeg pushes both Idss and Yfs down posing a limit to what can be achieved in terms of matching. Using 100 different Rdeg's values would in fact not increase yield notably. Many 2SJ74 will never match because they have to low Idss.
Attached Images
File Type: png 2SK170_2SJ74 deg all.png (57.3 KB, 493 views)
  Reply With Quote
Old 31st October 2012, 08:20 AM   #154
EUVL is offline EUVL  Europe
diyAudio Member
 
Join Date: Oct 2003
> Where is that F5X Pre?

On my table, waiting to be built.

> Many 2SJ74 will never match because they have to low Idss.

Get some 2SK170GRs.


Patrick
__________________
xen-audio.com
  Reply With Quote
Old 31st October 2012, 08:33 AM   #155
NicMac is offline NicMac  Italy
diyAudio Member
 
NicMac's Avatar
 
Join Date: Feb 2009
Quote:
Originally Posted by EUVL View Post
Get some 2SK170GRs.
I didn't think about that. You never run out of solutions do you
  Reply With Quote
Old 31st October 2012, 08:37 AM   #156
diyAudio Member
 
Join Date: Nov 2009
Location: Vienna
Should I ?

:-)

D.
  Reply With Quote
Old 31st October 2012, 08:44 AM   #157
EUVL is offline EUVL  Europe
diyAudio Member
 
Join Date: Oct 2003
These are all old problems known years ago, so are the solutions.
Nothing exciting.




Patrick
__________________
xen-audio.com
  Reply With Quote
Old 31st October 2012, 08:44 AM   #158
NicMac is offline NicMac  Italy
diyAudio Member
 
NicMac's Avatar
 
Join Date: Feb 2009
Right place - right time
Go ahead.
Nic
  Reply With Quote
Old 31st October 2012, 08:46 AM   #159
NicMac is offline NicMac  Italy
diyAudio Member
 
NicMac's Avatar
 
Join Date: Feb 2009
Quote:
Originally Posted by EUVL View Post
Nothing exciting.
Not excited. Just learning from others experience.
  Reply With Quote
Old 31st October 2012, 08:55 AM   #160
diyAudio Member
 
Join Date: Nov 2009
Location: Vienna
Quote:
Originally Posted by NicMac View Post
Of course your 5R1 value was chosen for a reason like most things you do


Of course there is the downside that each 2SJ74 will need a different Rdeg. But as a DIY'er I can live with this minor logistic complication.
Practically it's not a big deal, we just have to stock few resistors of these values, costs around 2 euros.

D.
  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
F5X -- the EUVL Approach EUVL Pass Labs 855 14th October 2013 03:50 AM
Potential EUVL F5X designed case user distribution check pchw Group Buys 1004 27th February 2013 03:32 PM
GB 2SK3497/2SJ618 for EUVL F5X or other projects pchw Group Buys 266 8th April 2012 06:05 PM
[B]PRP resistor group buy for the EUVL F5X build[/B] NicMac Group Buys 70 4th February 2012 04:20 PM
New Saburo Build thread Wha' DIYa know? Full Range 94 17th October 2010 04:49 PM


New To Site? Need Help?

All times are GMT. The time now is 05:37 AM.


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