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.

Building the ultimate NOS DAC using TDA1541A
Building the ultimate NOS DAC using TDA1541A
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 Today, 04:31 PM   #6721
batteryman is offline batteryman  United Kingdom
diyAudio Member
Join Date: Jun 2011
Location: SCOTLAND
Originally Posted by wlowes View Post
Like many, I have used Ian's PCB with the 1541a for several years. It works and to my ear sounds great at 44k to 192k without issue. But if I understand correctly that does not mean it is as good as it could be. If I am not mistaken, getting 15 bit depth vs 16 does not mean it does not work. It means we are running with a lower signal to noise ratio than the rated performance of the 1541a.
The way I see it is:

Losing the LSB is not that important as it is 1/65536th of the original resolution which won't affect the SNR or be audible. (Its not that the bits have all been shifted right resulting in 15bit data which would half the resolution to 32768)

All 16bits are processed by the board, but just that the 16th is (apparently) not clocked in - i.e. its missed so presumably its latch content will not change but all other 15 will be correct. The dac accuracy is only 0.5 - 1 LSB anyway so the LSB could be wrong by chance.

I have attached what I think is functionally equivalent of the 1541's input, register & latch (only 8 bits shown).
The data appears at the output of the register and is available to the latch when LE goes high according to the data sheet.

But according to Ian, the latch does not actually freeze the data until LE goes low, hence he says the LSB is not missed.

However, only in the multiplexed modes does the falling edge of LE latch the data so is Ian wrong, or is the datasheet not explicit or does it not actually matter?
Attached Images
File Type: jpg DACINPUT.jpg (27.6 KB, 38 views)

Last edited by batteryman; Today at 04:59 PM.
  Reply With Quote
Old Today, 06:56 PM   #6722
wlowes is offline wlowes  Canada
diyAudio Member
wlowes's Avatar
Join Date: Mar 2007
Location: Toronto
S/N Limits of
a CD is 96dB.
the TDA1541A is 98 - 110dB.
the Human auditory system is approximately 21 bits or 123dB.

I believe 15 bit audio is around 90dB. I suspect most of us will hear it. It may fall into the territory of do you hear difference in cables, but at least this one has a measurement.
  Reply With Quote
Old Today, 08:23 PM   #6723
Markw4 is offline Markw4  United States
diyAudio Member
Join Date: Jul 2016
Location: California
Undithered bit-depth reduction from 16-bits to 15 should be audible to at least some people.
  Reply With Quote


Building the ultimate NOS DAC using TDA1541AHide 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

New To Site? Need Help?

All times are GMT. The time now is 09:14 PM.

Search Engine Optimisation provided by DragonByte SEO (Pro) - vBulletin Mods & Addons Copyright © 2018 DragonByte Technologies Ltd.
Resources saved on this page: MySQL 15.79%
vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2018 DragonByte Technologies Ltd.
Copyright ©1999-2018 diyAudio