OLD THREAD DAC End by Andrea Ciuffoli - Page 93 - diyAudio
Go Back   Home > Forums > Commercial Sector > Vendor Forums > Quanghao Audio Design

Quanghao Audio Design Quanghao Audio Design is a producer of DIY Audiophile Kits and PCB boards, selected from many listening tests!

Reply
 
Thread Tools Search this Thread
Old 26th February 2010, 10:25 PM   #921
Salas is offline Salas  Greece
diyAudio Chief Moderator
 
Salas's Avatar
 
Join Date: Oct 2002
Location: Athens-Greece
Can you say there is no difference or error after looking at its bro +5V both form above and underneath on same board?
  Reply With Quote
Old 26th February 2010, 10:28 PM   #922
adamus is offline adamus  United Kingdom
diyAudio Member
 
Join Date: Apr 2008
no difference at all. I even braved the wife's eyes. They look identical. no bad traces, checked witha jultimeter.
  Reply With Quote
Old 26th February 2010, 10:34 PM   #923
Salas is offline Salas  Greece
diyAudio Chief Moderator
 
Salas's Avatar
 
Join Date: Oct 2002
Location: Athens-Greece
Lets do something? Can you short R15 or parallel a 10-33R on its legs?
  Reply With Quote
Old 26th February 2010, 10:41 PM   #924
adamus is offline adamus  United Kingdom
diyAudio Member
 
Join Date: Apr 2008
done.

no change
  Reply With Quote
Old 26th February 2010, 10:43 PM   #925
Salas is offline Salas  Greece
diyAudio Chief Moderator
 
Salas's Avatar
 
Join Date: Oct 2002
Location: Athens-Greece
That's weird. If everything is exactly as in the one next door and it does not behave I am out of more wits than changing the odd shot electrolytic.
  Reply With Quote
Old 26th February 2010, 10:46 PM   #926
adamus is offline adamus  United Kingdom
diyAudio Member
 
Join Date: Apr 2008
thats what i am going to try next. I'll sleep on it and have a go tomorrow.

Voltage over Q18 on the good board is 500-600 mv

Its less than half that on the 'bad board' but the idss is bigger
  Reply With Quote
Old 26th February 2010, 10:54 PM   #927
Salas is offline Salas  Greece
diyAudio Chief Moderator
 
Salas's Avatar
 
Join Date: Oct 2002
Location: Athens-Greece
R17 could eat mV if it is 100R instead 10R by mistake. Checked that also?
  Reply With Quote
Old 26th February 2010, 10:59 PM   #928
adamus is offline adamus  United Kingdom
diyAudio Member
 
Join Date: Apr 2008
yes, i have checked all the compenents visually and with a multimeter where possible.

Q18 will be my target tomorrow, but i can easily adjust vref to 4.8v+ so i have my doubts it will do anything. it all goes dodgey round q15.....

Last edited by adamus; 26th February 2010 at 11:01 PM.
  Reply With Quote
Old 27th February 2010, 09:38 AM   #929
adamus is offline adamus  United Kingdom
diyAudio Member
 
Join Date: Apr 2008
so, i tested the voltage with the 5v analogue line into the digital.... and guess what - it sits at exactly the same voltage.

All that faffing at it has to eb something on the dac board!
  Reply With Quote
Old 27th February 2010, 09:53 AM   #930
Salas is offline Salas  Greece
diyAudio Chief Moderator
 
Salas's Avatar
 
Join Date: Oct 2002
Location: Athens-Greece
Don't know what happens next, but the main reg should work ok without being connected. Does it?
  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
OLD THREAD Hi-end phono preamplifier by Andrea Ciuffoli quanghao Quanghao Audio Design 397 25th January 2014 06:16 PM
Cleo: End to End 24bit 192khz USB DAC with tube output bcherry DIY HiFi Supply 7 3rd July 2010 11:15 PM
The DAC End 2 by Andrea Ciuffoli pcb + most parts... prooptiki Swap Meet 7 31st May 2010 02:21 AM
Custom designed transformer for Andrea Ciuffoli 6c33c OTL AMP.... zxcxz Tubes / Valves 2 10th July 2009 04:14 PM
Andrea Ciuffoli Mosfet Amp DieterD Solid State 16 24th December 2001 05:56 AM


New To Site? Need Help?

All times are GMT. The time now is 03:35 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