Strange DC offset on Aleph 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 4th April 2012, 03:54 AM   #1
Dukja is offline Dukja  United States
diyAudio Member
 
Join Date: Sep 2011
Location: Oklahoma, US
Default Strange DC offset on Aleph 3

I just finished testing of my recent built DCB1 and was about to connect it to my Aleph 3 and found out something strange about A3's DC offset.

Before I turned on A3 with no input and no output connected, I measured about 1.5Vdc of speaker posts. This dc volt was there even when I disconnect power cord. I realized that it may be the voltage held by power filtering caps. After shorting each channel with a 10 ohm resistor, the dc volt was gone.

If I don't bleed the dc volt, the dc volt can stay there for more than a day. But as soon as I powered up A3, the dc offset dropped to about 30~40mV.

This is new to me, so I didn't resume the DCB1 trial and want to check with you guys to see if it is normal. My guess was that the dc volt should disappear if either some bleeding resistors were crossing the power caps or if the speaker was connected. The charges in the caps would just short out without hurting speakers. But since I have no bleeding resistor and no load connected, the discharge of power caps (why shows on speaker post) "looks like" a dc offset??

Thanks for you help to solve this mystery to me.

(I did do the total recap on this A3 and noted here)

Last edited by Dukja; 4th April 2012 at 03:59 AM.
  Reply With Quote
Old 4th April 2012, 08:28 AM   #2
Zen Mod is offline Zen Mod  Serbia
diyAudio Member
 
Zen Mod's Avatar
 
Join Date: Jan 2003
Location: ancient Batsch , behind Iron Curtain
stay cool

__________________
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 4th April 2012, 12:25 PM   #3
Dukja is offline Dukja  United States
diyAudio Member
 
Join Date: Sep 2011
Location: Oklahoma, US
So it was what it suppose to be? Nothing to worry about?
I saw my vintage Pioneer receiver has bleeding resistor, but I didn't see any for my A3. Is it good idea to put one or some on?

Thanks!

Last edited by Dukja; 4th April 2012 at 12:29 PM.
  Reply With Quote
Old 4th April 2012, 01:40 PM   #4
Zen Mod is offline Zen Mod  Serbia
diyAudio Member
 
Zen Mod's Avatar
 
Join Date: Jan 2003
Location: ancient Batsch , behind Iron Curtain
spk will bleed that
__________________
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 4th April 2012, 02:45 PM   #5
Dukja is offline Dukja  United States
diyAudio Member
 
Join Date: Sep 2011
Location: Oklahoma, US
Thanks a lot ZM! You are the great help as usual!

And I haven't figure the best way to add heatsink yet. I'll post the photo of my A3 after that.
  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
Strange DC offset with laptop audio output and some noise. Corben PC Based 0 16th December 2009 07:17 AM
Strange DC offset on T-amp Lostcause Class D 4 26th May 2007 12:17 PM
Aleph X DC offset tomchaoda Pass Labs 11 29th October 2004 09:37 PM
Strange offset behavior in Aleph 5 Kilentra Pass Labs 6 12th April 2004 06:01 PM
Aleph´s DC offset and sound Koy Pass Labs 2 8th October 2002 05:54 AM


New To Site? Need Help?

All times are GMT. The time now is 03:17 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