F4 power amplifier - Page 280 - 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 6th December 2008, 03:14 AM   #2791
diyAudio Member
 
albertli's Avatar
 
Join Date: Nov 2004
Location: Vancouver
SCD
May I ask where about are you in Vancouver.
  Reply With Quote
Old 8th December 2008, 07:28 PM   #2792
SCD is offline SCD  Canada
diyAudio Member
 
Join Date: Nov 2003
Location: 1/2 way up Vancouver Island
Hello Alberti:
I am over on the Island. About 1/2 way up in Campbell River
__________________
SCD
  Reply With Quote
Old 8th December 2008, 08:13 PM   #2793
EUVL is offline EUVL  Europe
diyAudio Member
 
Join Date: Oct 2003
> The sound is a bit too thin and not warm so far.

Add another 2 pairs of MOSFET per channel perhaps ??
I am sure you bought enough of them to try this out.




Patrick

PS My Aleph-X has 12 FETs per channel, and there are enough people who have 16. I think Nelson use something like 24, if my head still functions properly.
  Reply With Quote
Old 8th December 2008, 09:34 PM   #2794
The one and only
 
Nelson Pass's Avatar
 
Join Date: Mar 2001
Quote:
Originally posted by albertli
My F4 is singing for 4 hours now at 270mv with heatsink at 30C , mosfets at 40C and o.47 3w resistors at 48C.
I wonder if I run at higher bias would hurt the 0.47 3w resisitors.
If you have lots of heat sinking and your rails are at 24V or so, then the max
is around 700-900 mV. That will warm it up.

  Reply With Quote
Old 8th December 2008, 09:40 PM   #2795
Gyuri is offline Gyuri  Hungary
diyAudio Member
 
Gyuri's Avatar
 
Join Date: Nov 2003
Location: Budapest
Hello Papa!
Do we get some beautiful new game for Christmas?
Although the old ones are not all of them, an example are not yet for me yet F5.
And I got not bored of the even older ones.
Gyuri
__________________
Those who would have deserved the life they are all dead already. "Oh, my dead dears!" - Captain Cat
  Reply With Quote
Old 8th December 2008, 11:16 PM   #2796
The one and only
 
Nelson Pass's Avatar
 
Join Date: Mar 2001
Quote:
Originally posted by Gyuri
Hello Papa!
Do we get some beautiful new game for Christmas?
Although the old ones are not all of them, an example are not yet for me yet F5.
And I got not bored of the even older ones.
Gyuri
You have been exceptionally good this year, so for Xmas you get
a nice surprise.

A little bit of old and new to keep you warm through the winter.

  Reply With Quote
Old 8th December 2008, 11:27 PM   #2797
Paper mache horn fabricator
diyAudio Member
 
carpenter's Avatar
 
Join Date: Mar 2002
Location: Oregon City, Oregon
Hahahah.....

Speaking of warm: who needs a snow plow when you have class A amplifiers to keep the driveway clear!
__________________
I enjoy audio so much that I constructed a web site. I share my ideas at: www.inlowsound.com
  Reply With Quote
Old 9th December 2008, 01:16 AM   #2798
Formerly "jh6you". R.I.P.
 
Babowana's Avatar
 
Join Date: Jul 2006
Quote:
Originally posted by Nelson Pass


..., so for Xmas you get a nice surprise.



Gyuri, congratulations!

Attached Images
File Type: jpg birds on the branch.jpg (86.6 KB, 738 views)
  Reply With Quote
Old 9th December 2008, 06:24 AM   #2799
diyAudio Member
 
albertli's Avatar
 
Join Date: Nov 2004
Location: Vancouver
Patrick,

I certainly will try couple more pair just for warming up the heatsink and see how it go. I've to do this in the later days for I've to go Christmas shopping with my love one for the love ones.


-If you have lots of heat sinking and your rails are at 24V or so, then the max
is around 700-900 mV. That will warm it up.-

Nelson,

Thanks for the advice. I'm running both rails at 25v and 23v after loading. Both channels are running at 300mv now and it takes 3 hours to warm the heatsink at 36C. mosfets 50C and the 0.47R 60C. I don't know I would burn the 0.47R if I run the amp on more higher current.........

Wish everyone a Safe and Merry Christmas, Happy New Year too.
  Reply With Quote
Old 9th December 2008, 06:30 AM   #2800
EUVL is offline EUVL  Europe
diyAudio Member
 
Join Date: Oct 2003
0.9V across 0R47 is 1.9A. The resistor will see 1.7W; bit high but still OK. The transistor will see almost 50W, which is definitely high.

Therefore paralleling more FETs is the better solution, if money is no issue in that sense. I would suggest 1.3A per FET, which is about 600mV across 0R47.


Patrick
  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 11:49 PM
Power transformers versus amplifier output power..what is your option? destroyer X Solid State 38 9th May 2009 06:23 PM
McIntosh Power Amplifier Power Guard johnnyrt Solid State 2 23rd August 2007 11:22 PM
Output power for a power amplifier Progg70 Solid State 33 10th September 2006 09:44 AM
Amplifier 3000 Wats Rms Power + Smps Higcht Power Bestiality MARAVILLASAUDIO Class D 1 5th November 2004 05:06 PM


New To Site? Need Help?

All times are GMT. The time now is 03:10 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