Wolfson WM8741 Mono ??? - diyAudio
Go Back   Home > Forums > Source & Line > Digital Line Level

Digital Line Level DACs, Digital Crossovers, Equalizers, 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 7th January 2012, 01:25 PM   #1
diyAudio Member
 
Join Date: Feb 2008
Location: Beverly MA
Default Wolfson WM8741 Mono ???

I have a question about using this dac in MONO mode. The chip has separate resistor divider mid supply references for left and right channel. A total of six pins used. For mono would it be correct to tie the left and right sets together?

While I am at it, does anybody cut the ground plane for analog and digital now? I don't see that done on their eval board.
  Reply With Quote
Old 7th January 2012, 02:28 PM   #2
diyAudio Member
 
Join Date: Jan 2008
Location: Virginia
No, you don't "tie" them toghether! I don't see (in the pdf) any divider for the reference, just capacitors.
For the output you need to do the filter shown on page 62 of that pdf and, at the end of the "unballanced" left and right channels, add one more OpAmp to convert from the differential mono (presnt on the L and R unballanced) to unballanced mono - see the mono mode control register at page 48.

Why would you cut the ground planes? They are tied toghether inside the chip anyway!
Just separate the power supplies positive rails (or at least use an inductance between them, if power for digital comes from the analog side).
  Reply With Quote
Old 7th January 2012, 06:23 PM   #3
diyAudio Member
 
Join Date: Feb 2008
Location: Beverly MA
Quote:
Originally Posted by SoNic_real_one View Post
No, you don't "tie" them toghether! I don't see (in the pdf) any divider for the reference, just capacitors.
For the output you need to do the filter shown on page 62 of that pdf and, at the end of the "unballanced" left and right channels, add one more OpAmp to convert from the differential mono (presnt on the L and R unballanced) to unballanced mono - see the mono mode control register at page 48.

Why would you cut the ground planes? They are tied toghether inside the chip anyway!
Just separate the power supplies positive rails (or at least use an inductance between them, if power for digital comes from the analog side).
The resistors I refer to are shown in the block diagram, seems like two dividers are used for isolation which would not be needed for mono.


As a guy who design analog/mixed signal chips for a living I would agree that every node and component on a chip are connected at some level. The figure on pg 62 does suggest tying the analog and digital grounds together. Thanks for pointing that out. My last DAC was a PCM1704. It was common back then to split the ground planes and tie at single point.
Attached Images
File Type: jpg wm8741001.jpg (60.0 KB, 233 views)
  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
Wolfson WM8741 DAC boards (Ready to Play) mlihl Vendor's Bazaar 2 18th October 2013 02:13 PM
Wolfson WM8741 lduarte1973 Digital Line Level 30 28th December 2011 07:53 AM
FS: Wolfson WM8741 Eval Board + Power Supply + Torroid ChrisR1983 Swap Meet 1 28th October 2011 08:24 PM
Wolfson WM8741 Evaluation Board ChrisR1983 Digital Line Level 13 25th June 2011 01:41 PM
Wolfson WM8741 DIY kits/designs sarte Digital Line Level 1 2nd April 2011 08:10 AM


New To Site? Need Help?

All times are GMT. The time now is 12:49 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