PWM used in NAD M51 vs. DSD? - diyAudio
Go Back   Home > Forums > Source & Line > Digital Line Level
Home Forums Rules Articles diyAudio Store Gallery Wiki Blogs Register Donations FAQ Calendar Search Today's Posts Mark Forums Read

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
Thread Tools Search this Thread
Old 16th July 2012, 02:42 PM   #1
Dan_E10 is offline Dan_E10  United States
diyAudio Member
Join Date: May 2007
Default PWM used in NAD M51 vs. DSD?

Can anyone explain to me the practical differences between SACD's DSD or PDM and the PWM implemented in the NAD M51 DAC? I'd also be interested in any general discussion of the difference between PWM and DSD.
  Reply With Quote
Old 19th July 2012, 02:38 PM   #2
diyAudio Member
abraxalito's Avatar
Join Date: Sep 2007
Location: Hangzhou - Marco Polo's 'most beautiful city'. 700yrs is a long time though...
Blog Entries: 145
Send a message via Yahoo to abraxalito
My knowledge of these two is somewhat sketchy, but DSD is a one-bit approach, employing pulse-density modulation at a (1 bit) symbol rate of 2.8MHz (64X 44k1). NAD use a 7bit symbol at a rate of 16X 44k1.

NAD's scheme is based on hardware from Diodes Inc (formerly Zetex) and is a signal chain designed for a power output stage. Thus it uses PWM rather than PDM to minimize the number of transitions. Using DSD to drive a power output stage would incur much higher losses due to the high rate of transitions. In contrast NAD's approach has transitions at a 16X rate, but each symbol has a 'quantum of width' around 9nS from a 108MHz clock.

Given that Stanley Lipshitz has shown that DSD is a flawed format because its impossible to apply enough dither to linearize the single bit quantizer, NAD's approach appears to be superior because its by nature multibit, rather than single bit. However they're designed for different applications - there would be no point in storing PWM signals on an optical disk for example.
The heart ... first dictates the conclusion, then commands the head to provide the reasoning that will defend it. Anthony de Mello
  Reply With Quote


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
DSD Playback system, DSF Player + USB DDC + DSD Amplifier KOON3876 Digital Source 116 4th September 2012 11:20 PM
NAD M51 DDDAC- Eliminating incoming Jitter through conversion process from PCM to PWM tiefbassuebertr Digital Source 1 2nd July 2012 04:53 PM
Marantz cd63: PWM to DSD ? ash_dac Digital Source 0 24th February 2006 09:59 PM
M51 Mic stands Doug Everything Else 4 4th July 2003 10:36 AM

New To Site? Need Help?

All times are GMT. The time now is 03:55 PM.

vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2017 DragonByte Technologies Ltd.
Copyright 1999-2017 diyAudio

Content Relevant URLs by vBSEO 3.3.2