Searching for a simple DAC schematics - DIR9001+PCM1794 - diyAudio
Go Back   Home > Forums > Source & Line > Digital Source

Digital Source Digital Players and Recorders: CD , SACD , Tape, Memory Card, 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 20th August 2011, 07:19 PM   #1
Alexium is offline Alexium  Ukraine
diyAudio Member
 
Join Date: May 2010
Default Searching for a simple DAC schematics - DIR9001+PCM1794

Greetings.
I'm pretty sure I've seen several such DACs, but now I just can't find them. Could someone please throw a link at me?
Thanks in advance.
  Reply With Quote
Old 7th September 2011, 06:37 PM   #2
Alexium is offline Alexium  Ukraine
diyAudio Member
 
Join Date: May 2010
No suggestions? Datasheet schematics it is, then.
  Reply With Quote
Old 7th September 2011, 06:50 PM   #3
diyAudio Member
 
theAnonymous1's Avatar
 
Join Date: Feb 2004
Location: Anonymityville
Hi Alexium,

Attached is my schematic of a basic DIR9001 + PCM1794A. I've built it so I know it works. I later added a SRC4192 for upsampling and an external clock.

You need to come up with your own solution for an I/V stage.
Attached Files
File Type: pdf microdac.pdf (39.0 KB, 371 views)
  Reply With Quote
Old 7th September 2011, 06:50 PM   #4
ktta is offline ktta  Romania
diyAudio Member
 
Join Date: Nov 2004
Location: Bucharest
Hello. Try this:
DIR9001 DIR9001 SPDIF decoder
PCM1794 PCM1794A audio DAC
  Reply With Quote
Old 7th September 2011, 07:30 PM   #5
diyAudio Member
 
theAnonymous1's Avatar
 
Join Date: Feb 2004
Location: Anonymityville
I forgot there is an error in my schematic. The filter pin is on the wrong node of the passives. It's easy to see where it should go.
  Reply With Quote
Old 7th September 2011, 07:55 PM   #6
Alexium is offline Alexium  Ukraine
diyAudio Member
 
Join Date: May 2010
Thank you both very much!
theAnonymous1, how's the sound? My impression was passive I/U is not a good choice for PCM179x. What are the requirements to the subsequent amplifier?
Oh, and how can I adjust for twice a lower output current (I have a prototype board with PCM1798)? Should I double the 420 Ohm resistors? I'm quite a noob in electronics...

Last edited by Alexium; 7th September 2011 at 08:00 PM.
  Reply With Quote
Old 7th September 2011, 08:04 PM   #7
diyAudio Member
 
theAnonymous1's Avatar
 
Join Date: Feb 2004
Location: Anonymityville
Sound is excellent IMO, but I used an I/V stage similar to the one in the link ktta posted. When I made the schematic I was still undecided on what to do for I/V.

I'm sure there are lots of optimisations that can be done to my circuit, but where do they end once you start? You eventually end up with a cutting board size PCB with hundreds of components. I like to keep things simple.
  Reply With Quote
Old 7th September 2011, 08:08 PM   #8
Alexium is offline Alexium  Ukraine
diyAudio Member
 
Join Date: May 2010
Quote:
Originally Posted by theAnonymous1 View Post
I'm sure there are lots of optimisations that can be done to my circuit, but where do they end once you start?
Well, since I'm not a fanatic, for me they end once they stop sound better
Quote:
Originally Posted by theAnonymous1 View Post
I like to keep things simple.
Me too, thanks again for the design!

P.S. So, should I double the I/U ohms for twice a lower current? Or am I understanding its operation wrong?

P.P.S. Don't you, by any chance, have a PCB layout for this? I've tried to make a layout for just a bit bigger scheme, and the process make me feel like the dumbest person in the world. I guess topological cretinism is my diagnosis.

Last edited by Alexium; 7th September 2011 at 08:13 PM.
  Reply With Quote
Old 7th September 2011, 08:19 PM   #9
diyAudio Member
 
theAnonymous1's Avatar
 
Join Date: Feb 2004
Location: Anonymityville
The higher the R value the higher the output voltage (and noise) will be, and the lower the current draw on the DAC outputs.

If you base your design around my schematic, I would patch in the I/V LPF stage from the second link ktta posted.

Sorry, I'm horrible at math so you will need to figure out what R value is best for the 4mA p-p of the PCM1798.
  Reply With Quote
Old 7th September 2011, 08:30 PM   #10
Alexium is offline Alexium  Ukraine
diyAudio Member
 
Join Date: May 2010
Quote:
Originally Posted by theAnonymous1 View Post
The higher the R value the higher the output voltage (and noise) will be, and the lower the current draw on the DAC outputs.
So I actually understood it correctly, for once!
As far as I already have a half-assempled prototype board, I guess I'll experiment with I/U.
  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
DAC DIR9001+TDA1541A / Gigaworks Crystal DAC Bengali Digital Line Level 0 28th May 2010 08:11 PM
DAC Project PCM1794/1798 kevinkr Digital Source 18 29th October 2009 10:13 AM
dac pcm1794 vs cs4397 evert1 Digital Source 2 19th October 2008 02:36 PM
Usb Pcm1794 Dac andrei Digital Source 4 16th April 2006 02:02 AM
PCM1794 State off art DAC?? kimschips Digital Source 4 8th August 2005 10:42 PM


New To Site? Need Help?

All times are GMT. The time now is 09:03 PM.


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