F5X -- the EUVL Approach - Page 60 - 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 28th November 2011, 11:23 AM   #591
EUVL is offline EUVL  Europe
diyAudio Member
 
Join Date: Oct 2003
No fixed rules, just what I feel like.
Normally around 1/1000 to 1/20000 of the main C.

A good reference :

http://sound.westhost.com/power-supplies.htm

But feel free to experiment.


Patrick
__________________
xen-audio.com

Last edited by EUVL; 28th November 2011 at 11:47 AM.
  Reply With Quote
Old 28th November 2011, 11:59 AM   #592
Murdoc is offline Murdoc  Germany
diyAudio Member
 
Join Date: Nov 2010
Location: Sao Paulo
Tanks a lot!
  Reply With Quote
Old 28th November 2011, 01:11 PM   #593
ashaw is offline ashaw  Australia
diyAudio Member
 
Join Date: Jul 2006
A large capacitance has a large paracitic resistance and inductance in series with it. Adding a smaller capacitor improves the Power supply's high frequency response. A value of between 1uF and 10uF is appropriate after the reservoir capacitor. In high speed digital logic at least a 100nf cap should be plased next to each IC. With several such caps and several pF range caps also often being added.
  Reply With Quote
Old 28th November 2011, 02:53 PM   #594
diyAudio Member
 
Join Date: Feb 2005
Location: Melbourne
Bipass caps often produce complicated higher freq resonances, so you sometimes have to consider adding specific value 'snubber' ccts (R-C) to the paralleled capacitors to get the best results.

Fortunately, some combinations seem to work okay without the extra damping/filters but many don't - plenty of source material available about 'snubber' design, and other threads here, too.
__________________
... jh
  Reply With Quote
Old 28th November 2011, 03:45 PM   #595
dnewman is offline dnewman  United States
diyAudio Member
 
Join Date: Jan 2007
Quote:
Originally Posted by ashaw View Post
In high speed digital logic at least a 100nf cap should be plased next to each IC. With several such caps and several pF range caps also often being added.
While completely off-topic, I found the following recent article to be a nice illustrative write up of this,

Decoupling by Example

It seems that during a recent 74xx TTL contents, many of the entrants lacked use of bypass capacitors....

Dan
  Reply With Quote
Old 9th December 2011, 04:40 AM   #596
EUVL is offline EUVL  Europe
diyAudio Member
 
Join Date: Oct 2003
Just a teaser from the test team.

Smyslow sent me a square wave response of his F5X proto currently using 2SK1530 / 2SJ201 output devices, and 2SK170 / 2SJ74 front end cascodes.
Red is input; blue is output.

Fitzfish, meanwhile, also has his standard grounded X measured with some excellent distortion results.
But I'll leave him with the honour to tell you.

So we are making progress.




Patrick
Attached Images
File Type: jpg 111208 UF F5X Sq.jpg (105.7 KB, 535 views)
__________________
xen-audio.com

Last edited by EUVL; 9th December 2011 at 04:43 AM.
  Reply With Quote
Old 9th December 2011, 06:42 AM   #597
diyAudio Member
 
Join Date: Feb 2010
Location: Dallas Fort Worth area, Texas
Thanks Patrick.

It is exciting to see them working. I'll start with a taste of the measured performance and promise to post many more in the upcoming build thread.

This is THD in the grounded X configuration, 1W into 8 ohms. After some additional testing I'll be switching to floating X.

The total harmonic distortion is around 0.0006%.

More to come!
Dave
Attached Images
File Type: jpg FX5_GNDX_BAL.JPG (96.3 KB, 488 views)
  Reply With Quote
Old 9th December 2011, 08:27 AM   #598
diyAudio Member
 
Join Date: Jan 2006
Location: North west England
Exciting and thanks for posting. Looking forward ti building even more now.
  Reply With Quote
Old 9th December 2011, 11:12 AM   #599
diyAudio Member
 
Join Date: Oct 2009
Exciting news, excellent results.
  Reply With Quote
Old 9th December 2011, 11:26 AM   #600
EUVL is offline EUVL  Europe
diyAudio Member
 
Join Date: Oct 2003
You can see the balanced circuit and the good matching at work here, as all even harmonics are almost 10dB smaller than the next odd.

Only when you see distortion spectrums like this do you realise why there is so much fuzz about matching, .. etc.




Patrick
__________________
xen-audio.com
  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 08:39 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