DAC MSB adjustment - diyAudio
Go Back   Home > Forums > Source & Line > Digital Source

Digital Source Digital Players and Recorders: CD , SACD , Tape, Memory Card, etc.

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 16th February 2015, 06:03 PM   #1
diyAudio Member
 
Join Date: Jan 2009
Default DAC MSB adjustment

Hi there

I succeeded in MSB adjustment of PCM58P with pretty good results.

Now I would like to go further and adjust bit2, bit3 & bit4 too.
I'm not very smart with digital audio and i'm not sure how to proceed.
Should I adjust each bit alone with the others disconnected.
Should I begin with bit4, then bit3...MSB ?
Reverse order ?
Attached Images
File Type: jpg pcm58p-1.jpg (197.3 KB, 118 views)
File Type: jpg pcm58P_2.jpg (197.7 KB, 115 views)
  Reply With Quote
Old 17th February 2015, 09:12 AM   #2
diyAudio Member
 
Join Date: Mar 2004
Location: Budapest, Hungary
This tool should help:

DAC linearity test CD
  Reply With Quote
Old 17th February 2015, 06:19 PM   #3
diyAudio Member
 
Join Date: Jan 2009
thank you lcsalzar but it doesn't help at all
  Reply With Quote
Old 17th February 2015, 07:53 PM   #4
diyAudio Member
 
Join Date: Mar 2004
Location: Budapest, Hungary
If you describe what you don't understand I try to help.
  Reply With Quote
Old 18th February 2015, 08:44 AM   #5
diyAudio Member
 
Join Date: Jan 2009
I just don't see the link with my problem.

I explain myself.

In order to make the adjustment, I burned a CD with 3 minutes of 1KHz sinewave -30dB and put it into a CD player connected at the input jack of a PC sound card.
Then I used DSSF3 THD analyser (1KHz reference) to adjust MSB pin of PCM58P and get the lowest THD.
It worked great, the result on my HIFI system is now amazing.

Now I just want to adjust the 3 other pins, bit2, bit3 & bit3, trying to get a little more linearity.

That's the problem.
  Reply With Quote
Old 18th February 2015, 09:50 AM   #6
diyAudio Member
 
Join Date: Mar 2004
Location: Budapest, Hungary
I understand your problem. MSB adjustment will linearize at zero crossing. B2 adjustment will linearize at 1/2 full scale. B3 will linearize at 1/4 and 3/4 full scale, and so on. So you need a full scale dithered 1kHz test signal and an FFT analyzer. Adjust MSB then B2 then B3 then B4 for minimum spurious harmonics.
My linearity test CD method is a visual alternative, but one needs a measuring amplifier and an oscilloscope. Either method gives the same optimum.
  Reply With Quote
Old 18th February 2015, 02:57 PM   #7
diyAudio Member
 
Join Date: Jan 2009
OK, whatever I get some questions, I like to fully understand things.

1) What does mean "will linearize at zero crossing. B2 adjustment will linearize..."

2) "3/4 full scale" you write, isn't rather "1/8 full scale" ?

3) "full scale dithered 1kHz test signal" : I found "http://www.wavecor.co.uk/testdisk.htmlfoundhttp://www.wavecor.co.uk/testdisk.html”
Is it OK ? Otherwise, where may I found such a signal ?

4) Why a FFT analyzer, not a DHT ?

5) Lastly, when adjusting one pin, does the 3 others need to be disconnected ?
  Reply With Quote
Old 19th February 2015, 08:39 AM   #8
diyAudio Member
 
Join Date: Jan 2009
Quote:
Originally Posted by lcsaszar View Post
I understand your problem. MSB adjustment will linearize at zero crossing. B2 adjustment will linearize at 1/2 full scale. B3 will linearize at 1/4 and 3/4 full scale, and so on. So you need a full scale dithered 1kHz test signal and an FFT analyzer. Adjust MSB then B2 then B3 then B4 for minimum spurious harmonics.
My linearity test CD method is a visual alternative, but one needs a measuring amplifier and an oscilloscope. Either method gives the same optimum.

http://tube.fw.hu/lintest.zip no longer exists.

Do you know where I can find these files now ?
  Reply With Quote
Old 19th February 2015, 12:47 PM   #9
diyAudio Member
 
Join Date: Mar 2004
Location: Budapest, Hungary
The site closed, but I uploaded the tracks here:

DAC linearity test CD
DAC linearity test CD

You have to write them onto an audio CD.
  Reply With Quote
Old 20th February 2015, 09:39 AM   #10
diyAudio Member
 
Join Date: Jan 2009
Quote:
Originally Posted by lcsaszar View Post
The site closed, but I uploaded the tracks here:

DAC linearity test CD
DAC linearity test CD

You have to write them onto an audio CD.
Nice, thank's
  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
MSB MVC-1 8 channel remote volume control perceptionchanges Swap Meet 1 21st November 2014 07:50 AM
Need power supply for msb link iii dac rbwinterlink Power Supplies 0 7th April 2010 06:34 PM
DBX zonepro 1260 & MSB MVC advice pop4richard Digital Line Level 3 11th December 2009 12:45 AM
MSB Link III DAC - Frequency Lights fail to Illuminate! Anyone have the same issue? dtm1962 Digital Source 0 9th March 2008 08:39 AM
Any Idea for the MSB or I2S transmit??? hatasa Digital Source 0 11th June 2003 08:30 PM


New To Site? Need Help?

All times are GMT. The time now is 03:57 AM.


vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2015 DragonByte Technologies Ltd.
Copyright 1999-2015 diyAudio

Content Relevant URLs by vBSEO 3.3.2