DC bias (AMP6,41hz) - diyAudio
Go Back   Home > Forums > Amplifiers > Class D

Class D Switching Power Amplifiers and Power D/A conversion

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 2nd December 2007, 10:31 AM   #1
diyAudio Member
 
Join Date: Mar 2005
Location: Portugal
Default DC bias (AMP6,41hz)

Hi

At 6moons review of Trends Audio TA-10 they mention the importance of DC biasing the output.

So I measured the Dc offset of my AMP6 and the result is about +26mV and -28mv.The measurements are made without load and there is few millivolts of fluctuation.
Is this acceptable?
From my understanding this small amount of DC will not hurt the speakers,but how about the +/- difference between the channels.Is this "normal"?

There was a small line written by Jan at 41hz forum, about the possibility of adding a bias adjustment to AMP6 with couple of resistors and trimpots.Has anyone bothered to due such a mod? In that 6moons review they kind of make a big deal of the need of bias adjustment in class-d amps.

Thanks
__________________
xxx I should correct my spelling xxx
  Reply With Quote
Old 3rd December 2007, 09:18 PM   #2
diyAudio Member
 
Join Date: Aug 2004
Location: Uppsala,Sweden
Hi,
I don´t think there is a need for adjusting the bias if it doesn´t drift beyond the values you have given.

Here is a quote from Tripath´s technical information about the
TA0105A, please go to this information that I hope is still available if you want some more information, but the circuit there is only due to the TA 105A I think.

"Output offset voltages can be nulled by adjusting the 10KĦ potentiometer shown in Figure 5. Once set, and
the TA0105A reaches equilibrium, the offset does not typically drift. Offsets can typically be set to +/- 25mV.
R103 is used to adjust the offset of CH1, and R203 is used to adjust the offset of CH2. If a different TA0105A
is placed in the RB-TA0105A reference board, the offset of each channel will need to be re-trimmed."
__________________
Without wonderment,no life.
  Reply With Quote
Old 6th December 2007, 05:27 PM   #3
diyAudio Member
 
Join Date: Mar 2005
Location: Portugal
thanks for your reply

If this amount of offset is acceptable and no improvements in sound to expect,I will not bother to try the adjustment.
__________________
xxx I should correct my spelling xxx
  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
41Hz Amp6 BASIC minireview kristleifur Class D 20 26th July 2009 02:37 PM
Power transformer for 41hz amp6 ecl86 Class D 7 27th June 2007 10:06 PM
41Hz amp6 problem sharpi31 Class D 2 7th February 2007 10:37 AM
Help a noob troubleshoot his 41hz Amp6 migrane Class D 4 24th February 2006 03:56 PM
41Hz Amp6 cadbike Class D 9 8th January 2006 04:30 PM


New To Site? Need Help?

All times are GMT. The time now is 01:26 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