Go Back   Home > Forums > >
Home Forums Rules Articles diyAudio Store Blogs Gallery Wiki Register Donations FAQ Calendar Search Today's Posts Mark Forums Read

Digital Line Level DACs, Digital Crossovers, Equalizers, etc.

Oversampled DAC without digital filter vs NOS
Oversampled DAC without digital filter vs NOS
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 4th March 2019, 05:42 AM   #1
ygg-it is offline ygg-it  Italy
diyAudio Member
 
ygg-it's Avatar
 
Join Date: Feb 2008
Location: ITALY
Default Oversampled DAC without digital filter vs NOS

There is a point that is not clear to me, since I did not have the opportunity to listen or test to any oversampling DAC without a digital filter.

If, we say, the main drawback of "oversampling" (vs. "NOS") is the use of the digital filter (for ringing and artifacts problems), is it possible to create an "oversampling" DAC without a digital filter, but still including a smooth analog filter?

If someone prefers the NOS sound, is the "oversampled DAC but without digital filter" sound competitive (still natural and musical, like NOS BUT much more detailed, live OS)?

Or, even tricky, if an analog reconstruction output filter design works good and enough with a NOS, would it sound better in a oversampled DAC (but without digital filter)?
  Reply With Quote
Old 4th March 2019, 07:13 AM   #2
TNT is offline TNT  Sweden
diyAudio Member
 
Join Date: Apr 2003
Location: Sweden
http://lavryengineering.com/pdfs/lav...g-aliasing.pdf

OS means some sort of interpolation (zero stuffing or more intelligent) - in there lies the challenge!?

//
__________________
More distortion to the people!
  Reply With Quote
Old 4th March 2019, 07:15 AM   #3
analog_sa is offline analog_sa  Europe
diyAudio Member
 
analog_sa's Avatar
 
Join Date: Aug 2002
Location: Cascais
Oversampled DAC without digital filter vs NOS
So, what device in your view would be appropriate to perform the oversampling? Or are you still going to design it?

(question is for the thread starter)
  Reply With Quote
Old 4th March 2019, 07:28 AM   #4
Bill Coltrane is offline Bill Coltrane  Netherlands
diyAudio Member
 
Join Date: Oct 2018
Using no reconstruction filter in any dac will result in audible artefacts not pressent in the original filter.

If you want "natural and musical" sound, you need a reconstruction filter.
__________________
Subjective measurements with the proper protocol is the only thing that matters.
  Reply With Quote
Old 4th March 2019, 08:02 AM   #5
ygg-it is offline ygg-it  Italy
diyAudio Member
 
ygg-it's Avatar
 
Join Date: Feb 2008
Location: ITALY
Quote:
Originally Posted by Bill Coltrane View Post
Using no reconstruction filter in any dac will result in audible artefacts not pressent in the original filter.

If you want "natural and musical" sound, you need a reconstruction filter.
Yes, but my original question was: can I do this filter (in an oversampled DAC) 100% in analog domain and not partially digital and partially analog like the most of oversampled DAC? How this sounds in comparison to NOS (with analog filter)?

Last edited by ygg-it; 4th March 2019 at 08:06 AM.
  Reply With Quote
Old 4th March 2019, 08:28 AM   #6
abraxalito is offline abraxalito  United Kingdom
diyAudio Member
 
abraxalito's Avatar
 
Join Date: Sep 2007
Location: Hangzhou - Marco Polo's 'most beautiful city'. 700yrs is a long time though...
Send a message via Yahoo to abraxalito
If you oversample but use no digital filtering at all, the primary advantage of oversampling (the ability to use a simpler analog filter) is lost. With no digital filter, oversampling must simply repeat the previous sample for the interpolated value(s) (zero order hold) and that's equivalent to no oversampling.
__________________
I know you think you understand what you thought I said but I'm not sure you realize that what you heard is not what I meant - Alan Greenspan
  Reply With Quote
Old 4th March 2019, 08:49 AM   #7
ygg-it is offline ygg-it  Italy
diyAudio Member
 
ygg-it's Avatar
 
Join Date: Feb 2008
Location: ITALY
Quote:
Originally Posted by abraxalito View Post
If you oversample but use no digital filtering at all, the primary advantage of oversampling (the ability to use a simpler analog filter) is lost. With no digital filter, oversampling must simply repeat the previous sample for the interpolated value(s) (zero order hold) and that's equivalent to no oversampling.
But if I oversample n times without the digital filter, I can use a gentle analog filter cut much higher (with a cut off frequency n times higher than NOS). Or not?
  Reply With Quote
Old 4th March 2019, 08:57 AM   #8
abraxalito is offline abraxalito  United Kingdom
diyAudio Member
 
abraxalito's Avatar
 
Join Date: Sep 2007
Location: Hangzhou - Marco Polo's 'most beautiful city'. 700yrs is a long time though...
Send a message via Yahoo to abraxalito
Say you decided to repeat the previous sample 3 times, giving you an update rate of 4X the original. You've still got images which start at 24.1kHz because you've not removed those through use of digital filtering. Meaning you've got to build a very sharp analog filter to eliminate them, just as for NOS.
__________________
I know you think you understand what you thought I said but I'm not sure you realize that what you heard is not what I meant - Alan Greenspan
  Reply With Quote
Old 4th March 2019, 10:19 AM   #9
analog_sa is offline analog_sa  Europe
diyAudio Member
 
analog_sa's Avatar
 
Join Date: Aug 2002
Location: Cascais
Oversampled DAC without digital filter vs NOS
Quote:
Originally Posted by abraxalito View Post
Say you decided to repeat the previous sample 3 times, giving you an update rate of 4X the original. You've still got images which start at 24.1kHz
I don't understand this. If your new sample rate is 4x why would you have such low images? Is this not the same as upsampling with respect to images?
  Reply With Quote
Old 4th March 2019, 10:25 AM   #10
abraxalito is offline abraxalito  United Kingdom
diyAudio Member
 
abraxalito's Avatar
 
Join Date: Sep 2007
Location: Hangzhou - Marco Polo's 'most beautiful city'. 700yrs is a long time though...
Send a message via Yahoo to abraxalito
You only get to have your images at higher frequencies (which are always there, even with NOS) if you remove the lower freq ones with a digital filter. Simply repeating the same sample 3 more times doesn't do any image removal.
__________________
I know you think you understand what you thought I said but I'm not sure you realize that what you heard is not what I meant - Alan Greenspan
  Reply With Quote

Reply


Oversampled DAC without digital filter vs NOSHide 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

Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
FIR Digital Filter DSP neededandwanted Parts 1 9th April 2009 01:44 AM
Oversampled TDA1541(a) I2S format? andrew_whitham Digital Source 25 17th April 2006 07:10 PM
Toshiba 3950 w/ John Swenson Mod vs. 1543 Non-Oversampled Dac Tuber Digital Source 6 28th November 2004 01:42 PM
Kwak clock and Guido Tent oscillator in a TDA1541 zer-oversampled cd player Dr.H Digital Source 4 10th May 2003 09:42 AM
Digital (DSP) filter magnus Digital Source 12 9th February 2003 12:17 PM


New To Site? Need Help?

All times are GMT. The time now is 09:36 PM.


Search Engine Optimisation provided by DragonByte SEO (Pro) - vBulletin Mods & Addons Copyright © 2019 DragonByte Technologies Ltd.
Resources saved on this page: MySQL 14.29%
vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2019 DragonByte Technologies Ltd.
Copyright ©1999-2019 diyAudio
Wiki