Aleph 2 uneven temperatures - Page 3 - 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 23rd January 2013, 09:59 AM   #21
AAAudio is offline AAAudio  United States
diyAudio Member
 
Join Date: Dec 2012
Thank you. Now a mosfet is cold!

I am thinking the batch was flawed. I ordered 1% 5w 1ohm resistors for the mosfet source. I hope this improves the matching!

The funny thing is that bias drops with time. it is supposed to be 3A and that value is reached only in the beginning when the amp is cold. then it drops to 2.56A. could it be a "cold" mosfet is causing this?
  Reply With Quote
Old 23rd January 2013, 10:09 AM   #22
Zen Mod is offline Zen Mod  Serbia
diyAudio Member
 
Zen Mod's Avatar
 
Join Date: Jan 2003
Location: ancient Batsch , behind Iron Curtain
no pictures , no measurements in important points , and you are expecting even additional confirmation of everything we replied to you ?

I understand lack of experience , but you really need to read what people are replying

temperature equilibrium is just that - equilibrium - it doesn't matter is it on 35 or 50C

crank up that bias and enjoy
__________________
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 5th February 2013, 07:55 PM   #23
AAAudio is offline AAAudio  United States
diyAudio Member
 
Join Date: Dec 2012
Click the image to open in full size.



Inviato dal mio GT-I9001 con Tapatalk 2
  Reply With Quote
Old 5th February 2013, 07:56 PM   #24
AAAudio is offline AAAudio  United States
diyAudio Member
 
Join Date: Dec 2012
Click the image to open in full size.

Inviato dal mio GT-I9001 con Tapatalk 2
  Reply With Quote
Old 5th February 2013, 07:58 PM   #25
AAAudio is offline AAAudio  United States
diyAudio Member
 
Join Date: Dec 2012
I am waiting for some components for second channel. Strange thing is that positive rail sees less current than negative rail. 3.5A vs 3.1A

I am waiting for matched irf9610 to reduce dc offset

Inviato dal mio GT-I9001 con Tapatalk 2
  Reply With Quote
Old 5th February 2013, 08:00 PM   #26
AAAudio is offline AAAudio  United States
diyAudio Member
 
Join Date: Dec 2012
Ah i forgot the heatsinks do still get quite warm but i plan large undervolted fans under it (20cm x2). the heatsinks weigh 15kg each 60x60x10cm

Inviato dal mio GT-I9001 con Tapatalk 2
  Reply With Quote
Old 5th February 2013, 08:01 PM   #27
diyAudio Member
 
MEGA_amp's Avatar
 
Join Date: Oct 2003
Location: CT
Remove R19 (ref Aleph2 schem) and leave open. Sweet amps!! Are those wheels I see? I've used some 12V Noctua fans, seen in CPU heatsinks, undervolted by a few volts, they are silent.

Last edited by MEGA_amp; 5th February 2013 at 08:03 PM.
  Reply With Quote
Old 5th February 2013, 08:03 PM   #28
AAAudio is offline AAAudio  United States
diyAudio Member
 
Join Date: Dec 2012
Thanks. Yes i removed r19 completely. I plan.on installing two ixys brick mosfets and.make thwm interchangeable. Yes there are wheels so i can move it around (80kg + )

Inviato dal mio GT-I9001 con Tapatalk 2
  Reply With Quote
Old 5th February 2013, 08:04 PM   #29
AAAudio is offline AAAudio  United States
diyAudio Member
 
Join Date: Dec 2012
Second channel is still missing but i am also planning to add 250000uf of caps per channel to allow for higher bias

Inviato dal mio GT-I9001 con Tapatalk 2
  Reply With Quote
Old 5th February 2013, 08:07 PM   #30
diyAudio Member
 
MEGA_amp's Avatar
 
Join Date: Oct 2003
Location: CT
more bias doesn't necessarily require more PS caps, however it will help lower PS ripple. Is that 6X60000uF per channel? If it is, I think you have enough.
  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
Do you measure component temperatures? Greg Erskine Solid State 26 26th January 2011 09:00 AM
Playing stereo in cold temperatures ? Robcrx Car Audio 3 15th March 2010 05:18 PM
tube temperatures woodturner-fran Tubes / Valves 3 13th April 2006 06:27 PM
Survey - Actual Amp Temperatures keypunch Solid State 8 20th December 2004 12:57 AM
Question about Soldering Temperatures KT Chip Amps 6 8th June 2004 11:07 PM


New To Site? Need Help?

All times are GMT. The time now is 06:54 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