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
Reply
 
Thread Tools Search this Thread
Old 16th July 2006, 09:01 PM   #591
ecdesigns is offline ecdesigns  Netherlands
diyAudio Member
 
Join Date: May 2006
Location: Holland
Default multiple DAC chip's and resolution

Hi dddac,

Thanks for your reply [post#589]

Yes, the TDA1543 sounds better than I had expected, especially when multiples are used. With the standard NOS DAC setup (multiple TDA1543's in parallell) you get about 441 sample points for a 100 Hz sinewave, with a 1.25 KHz sinewave about 35 sample points. Each sample point can have 65536 possible values theoretically.

Now with the 16 DAC D-I technique, a 100 Hz sinewave has 7056 sample points, a 1.25 KHz sinewave about 564 sample points. Now each sample point can have 1048576 possible values theoretically. DAC current about 750mA, power consumption about 5.6W.

The resolution with 32 DAC D-I technique, 100 Hz sinewave, 14112 sample points. 1.25 KHz sinewave 1128 sample points. Samples can have 2097152 possible values theoretically. DAC current about 1.5A, power consumption about 11.25W.

With 64 DAC chips, 100 Hz sinewave, 28224 sample points. 1.25 KHz sinewave 2257 sample points. Samples can have 4194304 possible values theoretically. DAC current about 3A, power consumption about 22.5W.

This is quite a bit different than just parallelling DAC's, the output is way smoother and needs no filtering. The phase response is still true linear, and the trebles are crystal clear without interference.

That is what I mean by the D-I technique produces a smoother output signal that needs no filtering. The high frequency rolloff and linear interpolation errors still exist, but in exchange you get very high resolution and true linear phase response. So it seems it's either true sinewave shapes at high frequencies at the cost of phase errors. Or the D-I technique "problems" mentioned above, when one has to work with a 44.1 KHz sampled signal.

I added a photograph of the messy prototype setup, it's clean unfiltered 1.25 KHz sinewave 564 sample point output, and a view of the power supply to give a indication of power consumption of the complete 16 DAC setup.
Attached Images
File Type: jpg di16.jpg (90.6 KB, 1480 views)
  Reply With Quote
Old 16th July 2006, 09:11 PM   #592
stefanobilliani is offline stefanobilliani  Italy
diyAudio Member
 
Join Date: Jun 2002
Location: Italy
Default Re: exploring the limits

Quote:
Originally posted by -ecdesigns-
Hi all,

What about the TDA1543 reference pin? seems it musn't be connected directly as high frequency interference occurs.

If you cascode the output is possible to disconnect the reference pin .
That also permit a very high immunity from digital noise ...
  Reply With Quote
Old 16th July 2006, 09:44 PM   #593
ecdesigns is offline ecdesigns  Netherlands
diyAudio Member
 
Join Date: May 2006
Location: Holland
Default I/V stage

Hi maxlorenz,

Thanks for your reply [post#590]

The TDA1543's can have both an active or passive I/V stage, and the setup can be both differential (DC coupled) or single ended (capacitor needed). When a single ended setup is desired, the tap's for the even numbered DAC's serial data don't need to be inverted.
  Reply With Quote
Old 16th July 2006, 09:57 PM   #594
tubee is offline tubee  Netherlands
diyAudio Member
 
tubee's Avatar
 
Join Date: Jul 2004
Location: Netherlands
Very interesting this TDA1543 experiment. One big pro is the easy implementation of it. Matter of fact is that i bought a cheap 2nd hand cdp with this dac, and i didn't dislike the sound, its unmodified allready slightly more transparent compared to 1541. John, where did you get the dac chips from, Reichelt?

I am happy to hear also Dutchman liked the 1541 D-I dac.
__________________
Daisy Bell
  Reply With Quote
Old 16th July 2006, 10:14 PM   #595
maxlorenz is online now maxlorenz  Chile
diyAudio Member
 
maxlorenz's Avatar
 
Join Date: Oct 2003
Location: osorno , Chile
Quote:
I am happy to hear also Dutchman liked the 1541 D-I dac.
Yeah...a pitty that he's on a hurry and couldn't share more details

Quote:
The TDA1543's can have both an active or passive I/V stage, and the setup can be both differential (DC coupled) or single ended (capacitor needed). When a single ended setup is desired, the tap's for the even numbered DAC's serial data don't need to be inverted.
Most excellent news!
Did Dutchman heard the 1543 version?

Gratefully yours,
M
  Reply With Quote
Old 17th July 2006, 02:16 AM   #596
MGH is offline MGH  United States
diyAudio Member
 
Join Date: Jul 2004
Location: Texas
Hi EC,

Which sounds better between the DI-1543 and DI-1541A DAC?
  Reply With Quote
Old 17th July 2006, 06:56 AM   #597
agent.5 is offline agent.5  United States
diyAudio Member
 
Join Date: Aug 2003
Location: San Francisco, CA
Just another crazy idea. If you are using 64 TDA1543 chips, the required I/V resistor must be very low, how about use a microphone transformer and use the DCR within the transformer as IV?

I have no idea if this will work. But it may.
  Reply With Quote
Old 17th July 2006, 08:13 AM   #598
ErikdeBest is offline ErikdeBest  Switzerland
diyAudio Member
 
Join Date: Mar 2003
Location: Zürich
Hi all

Last Friday I visited ec-designs, curious about his system. I liked it a lot, but as everything was new for me I can not say anything about the quality of the D-I Dac on its own. What I can say is that the guy knows what he is talking about - and he even succeded in explaining me the debat between the NOS and OS.

I also heard the 8x TDA1543 version, but this was on another system, another room. But sure, not bad either! I was surprised to learn that with the 1k resistor on the REF pin the power consumption of the TDA's decreased by a half, so no cooling is needed.

And overall - what EC designs accomplished in 2 to 3 years of work is astounishing.
  Reply With Quote
Old 17th July 2006, 10:40 AM   #599
dddac is offline dddac  Germany
diyAudio Member
 
Join Date: Jul 2003
Location: Wiesbaden
Quote:
Originally posted by agent.5
Just another crazy idea. If you are using 64 TDA1543 chips, the required I/V resistor must be very low, how about use a microphone transformer and use the DCR within the transformer as IV?

I have no idea if this will work. But it may.


It will work fo DC only than .... For AC you will have the transformed impedance from the load being the R in I/V ...

plus the DC will saturate the coil

ergo, won't work...
__________________
www.dddac.com
Happy listening and building
  Reply With Quote
Old 17th July 2006, 09:36 PM   #600
ecdesigns is offline ecdesigns  Netherlands
diyAudio Member
 
Join Date: May 2006
Location: Holland
Default I/V stage OP-amps

Hi stefanobilliani,

Thanks for your tip [post#592]

I used a active I/V stage (OP-amp) for precision, so I needed a average reference voltage of all DAC chip's for the NON-inverting input since the output had to be fully DC coupled with absolute minimum drift. I can't use ground as the DC component would be too high. I tested some cascode setups with both transistors and JFET's and compared them to the op-amp stage. Both noise and drift was higher, and it was less accurate. So I continued testing op-amps that were fully stable at the high frequencies produced by the combined DAC outputs. The AD823 seems to work very well in the I/V stage.

But I just noticed another interesting op-amp on this site, the LT1469. As I need a very fast op-amp, this one just might be it.
  Reply With Quote

Reply


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 10:32 PM.


Search Engine Optimisation provided by DragonByte SEO (Pro) - vBulletin Mods & Addons Copyright © 2018 DragonByte Technologies Ltd.
Resources saved on this page: MySQL 15.00%
vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2018 DragonByte Technologies Ltd.
Copyright ©1999-2018 diyAudio
Wiki