F4 power amplifier - Page 198 - 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 3rd February 2008, 05:30 PM   #1971
diyAudio Member
 
Andrzej Sochon's Avatar
 
Join Date: Nov 2007
Location: Warsaw
Quote:
Originally posted by apassgear

Farads are good up to a point, depending on the amp bias ....I do bypass the amps PSU with some oiled polyprops cans on the 40 to 80 uf ...I also use these caps for lineamps some 25uf bypassed also with small film caps (0.1uf) with outstanding results. .......I suggest you try them and have your ears be the judge.

Hi,
I add few capacitors to my f4 lineamps, see attached schematics. Capacitors at input are soldered directly to the jfet legs and input ground. 220uF capacitors at output are C5 and C6 on Peter Daniel board, according to his suggestion.
Overall results are very nice for my ears. javascript:smilie('')
wink
Best Regards,
a.
Attached Images
File Type: jpg f4_as_mod_2008.02.02_.jpg (81.1 KB, 812 views)
  Reply With Quote
Old 3rd February 2008, 06:48 PM   #1972
cviller is offline cviller  Denmark
diyAudio Member
 
cviller's Avatar
 
Join Date: Dec 2005
Location: Copenhagen
Blog Entries: 2
Quote:
Originally posted by Andrzej Sochon



Hi,
I add few capacitors to my f4 lineamps, see attached schematics. Capacitors at input are soldered directly to the jfet legs and input ground. 220uF capacitors at output are C5 and C6 on Peter Daniel board, according to his suggestion.
Overall results are very nice for my ears. javascript:smilie('')
wink
Best Regards,
a.

Sorry for asking, but what is the reason for providing an ac path from out to signal in gnd? If you want to make global feedback wouldn't it be more obvious to apply it to the signal and not gnd?
  Reply With Quote
Old 3rd February 2008, 07:44 PM   #1973
Blues is offline Blues  United States
Lightning In A Bottle
diyAudio Member
 
Blues's Avatar
 
Join Date: Sep 2003
Location: The Milky Way
Additional +/- supply filtering of front and output stages...
__________________
Life simplified! Leap into the Warpspeed wormhole... http://www.6moons.com/audioreviews/warpspeed/1.html
  Reply With Quote
Old 3rd February 2008, 07:57 PM   #1974
diyAudio Member
 
Andrzej Sochon's Avatar
 
Join Date: Nov 2007
Location: Warsaw
Quote:
Originally posted by Andrzej Sochon
Capacitors at input are soldered directly to the jfet legs and input ground. 220uF capacitors at output are C5 and C6

Quote:
Originally posted by cviller
what is the reason for providing an ac path from out to signal in gnd? ....

capacitors at output are not on the signal in gnd - Peter Daniel made on his amp board separate gnd point for C5 and C6 to be wired to PSU gnd...so there is no feedback loop.
a.
  Reply With Quote
Old 3rd February 2008, 08:04 PM   #1975
diyAudio Member
 
Andrzej Sochon's Avatar
 
Join Date: Nov 2007
Location: Warsaw
Quote:
Originally posted by Andrzej Sochon

capacitors at output are not on the signal in gnd - Peter Daniel made on his amp board separate gnd point for C5 and C6 to be wired to PSU gnd...so there is no feedback loop.
a.
I put comments around GND points on the schematics, see the picture below
a.
Attached Images
File Type: jpg f4_as_mod+_2008.02.02.jpg (82.7 KB, 720 views)
  Reply With Quote
Old 3rd February 2008, 08:04 PM   #1976
cviller is offline cviller  Denmark
diyAudio Member
 
cviller's Avatar
 
Join Date: Dec 2005
Location: Copenhagen
Blog Entries: 2
I was not talking about the rail caps, but the 100u and 22n placed on the input.
  Reply With Quote
Old 3rd February 2008, 08:07 PM   #1977
cviller is offline cviller  Denmark
diyAudio Member
 
cviller's Avatar
 
Join Date: Dec 2005
Location: Copenhagen
Blog Entries: 2
Here is the path I'm talking about.
Attached Images
File Type: jpg f4_as_mod_2008.02.02.jpg (76.4 KB, 739 views)
  Reply With Quote
Old 3rd February 2008, 08:10 PM   #1978
Blues is offline Blues  United States
Lightning In A Bottle
diyAudio Member
 
Blues's Avatar
 
Join Date: Sep 2003
Location: The Milky Way
Quote:
Originally posted by cviller
I was not talking about the rail caps, but the 100u and 22n placed on the input.
Same thing...+/- supply filters for the front end.
__________________
Life simplified! Leap into the Warpspeed wormhole... http://www.6moons.com/audioreviews/warpspeed/1.html
  Reply With Quote
Old 3rd February 2008, 08:19 PM   #1979
diyAudio Member
 
Andrzej Sochon's Avatar
 
Join Date: Nov 2007
Location: Warsaw
Quote:
Originally posted by cviller
I was not talking about the rail caps, but the 100u and 22n placed on the input.
I understand what you mean; but in my opinion 100u and 22n does not provide an ac path from out to signal in gnd. Capacitors added by me are between In GND and internal +/- DC sub-rails, creating additional filter.
a.
  Reply With Quote
Old 3rd February 2008, 08:20 PM   #1980
cviller is offline cviller  Denmark
diyAudio Member
 
cviller's Avatar
 
Join Date: Dec 2005
Location: Copenhagen
Blog Entries: 2
Quote:
Originally posted by Blues


Same thing...+/- supply filters for the front end.

That only holds true to the old revision of F4, but this one has the output swing (simple voltage divider between the 1k resistors) at those points.
  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
Rockford Fosgate Power 20001 bd amplifier power rating?? pachoorion Car Audio 8 8th May 2011 10:49 PM
Power transformers versus amplifier output power..what is your option? destroyer X Solid State 38 9th May 2009 05:23 PM
McIntosh Power Amplifier Power Guard johnnyrt Solid State 2 23rd August 2007 10:22 PM
Output power for a power amplifier Progg70 Solid State 33 10th September 2006 08:44 AM
Amplifier 3000 Wats Rms Power + Smps Higcht Power Bestiality MARAVILLASAUDIO Class D 1 5th November 2004 04:06 PM


New To Site? Need Help?

All times are GMT. The time now is 05:34 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