Go Back   Home > Forums > Source & Line > Digital Line Level

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
Reply
 
Thread Tools Search this Thread
Old 21st September 2012, 07:37 PM   #1
diyAudio Member
 
Join Date: Oct 2004
Location: Aalborg, Denmark
Default Bragi, an Asynchronous ES9023 DAC with isolated I2S Input and Alps RK27 Volume pot

A simple board based on the ES9023 DAC running asynchronously with an 50 MHz oscillator

It has isolated I2S inputs, Analog volume control with Alps RK27 Pot.

Bottom layer is a dedicated ground plane with no interruptions.

Should be supplied with 6 VDC, which is regulated down to 5 VDC by LT1763 for use with the ADuM5000 isolated DC-DC Converter powering the isolated I2S inputs and going to the 3 separate 3.3 VDC LT1761 regulators used for powering the ES9023 IC, ADuM3440 digital isolator and the 50 MHz oscillator.
Attached Images
File Type: png Bragi_Schematic.png (57.8 KB, 1357 views)
File Type: png Bragi_Gerber.png (43.2 KB, 1303 views)

Last edited by Neutrality; 21st September 2012 at 07:45 PM.
  Reply With Quote
Old 22nd September 2012, 07:54 PM   #2
diyAudio Member
 
Join Date: Oct 2004
Location: Aalborg, Denmark
I did a few final touches to the board.

Shortened it 5mm, added a ferrite in the supply line just before the oscillator, put a few more GND vias in the board at critical places, reduced the size of the isolated I2S input ground plane area.
Attached Images
File Type: png Bragi_Gerber_Tuned.png (34.9 KB, 1209 views)
  Reply With Quote
Old 22nd September 2012, 08:50 PM   #3
diyAudio Moderator Emeritus
 
jean-paul's Avatar
 
Join Date: Sep 2002
Location: Germany
Hi the more ES9023 DACs the merrier. I think it will perform better without the RK27 though (or add a simple buffer after it). Please add a bead to the power supply pin of ES9023 too and feed it 3.6 V.

Interesting that you use 10 F for the charge pump circuit. Did you already build it ?
__________________
It's only audio. Official member of the Norske Brillegeit Gang.

Last edited by jean-paul; 22nd September 2012 at 08:56 PM.
  Reply With Quote
Old 23rd September 2012, 10:06 AM   #4
diyAudio Member
 
Join Date: Oct 2004
Location: Aalborg, Denmark
Quote:
Originally Posted by jean-paul View Post
Hi the more ES9023 DACs the merrier. I think it will perform better without the RK27 though (or add a simple buffer after it). Please add a bead to the power supply pin of ES9023 too and feed it 3.6 V.

Interesting that you use 10 F for the charge pump circuit. Did you already build it ?
ES9023 should have no problem with a 20K pot. Adding a ferrite bead to the ES9023 supply is a good idea. 3.6V just gives 2Vrms out instead of 1.9Vrms, no big difference.

Havent built it yet, just designing.

The 10uF between Cn and Cp is not a value that I have fully decided on, it could be lower than that and probably should be.
  Reply With Quote
Old 23rd September 2012, 10:52 AM   #5
diyAudio Moderator Emeritus
 
jean-paul's Avatar
 
Join Date: Sep 2002
Location: Germany
Just try the 3.6 V. You will like it better. The reason for this is not 1.9 versus 2 V.

About the RK27: the ES9023 has no problem with it but you will have a higher output impedance at normal volume. In practice it will be better to use the potentiometer at the receiving end. I have doubts if the RK27 is good enough for this application. My guess is that the DAC will sound better without it but that is easy to try out.
__________________
It's only audio. Official member of the Norske Brillegeit Gang.

Last edited by jean-paul; 23rd September 2012 at 10:58 AM.
  Reply With Quote
Old 23rd September 2012, 04:35 PM   #6
syklab is online now syklab  Hong Kong
diyAudio Member
 
Join Date: Jul 2009
Location: Hong Kong
Quote:
Originally Posted by Neutrality View Post
A simple board based on the ES9023 DAC running asynchronously with an 50 MHz oscillator

It has isolated I2S inputs, Analog volume control with Alps RK27 Pot.

Bottom layer is a dedicated ground plane with no interruptions.

Should be supplied with 6 VDC, which is regulated down to 5 VDC by LT1763 for use with the ADuM5000 isolated DC-DC Converter powering the isolated I2S inputs and going to the 3 separate 3.3 VDC LT1761 regulators used for powering the ES9023 IC, ADuM3440 digital isolator and the 50 MHz oscillator.
Hi,
What is IC6 and IC7 ?
  Reply With Quote
Old 23rd September 2012, 05:23 PM   #7
diyAudio Member
 
Join Date: Oct 2004
Location: Aalborg, Denmark
Quote:
Originally Posted by syklab View Post
Hi,
What is IC6 and IC7 ?
IC6 is ADuM3440 digital isolator, isolates the I2S inputs.

IC7 is ADuM5000 isolated DC-DC converter. Provides power to the I2S isolator on the input side.

However, Im revising the design, adding a few ferrites, tweaking the layout and part values.

Gone is IC7, it basically draws way too much current(about 33% efficiency) and according to the datasheet it could put out some nasty switching noise, which I do not want in my circuit.

So now the digital isolator has to be supplied with a separate 3V3 supply on the input side.
  Reply With Quote
Old 23rd September 2012, 07:00 PM   #8
diyAudio Member
 
Join Date: Oct 2004
Location: Aalborg, Denmark
And its done.
Attached Images
File Type: png Bragi_Gerber.png (75.8 KB, 1109 views)
  Reply With Quote
Old 23rd September 2012, 08:54 PM   #9
diyAudio Moderator Emeritus
 
jean-paul's Avatar
 
Join Date: Sep 2002
Location: Germany
You might want to use a large cap for the positive supply pin of ES9023. 100 F or more. If you are going to use connector blocks for the outputs (if only for testing) the pads for those must be moved somewhat to the left or you will have to mount the PCB with only 3 screws
__________________
It's only audio. Official member of the Norske Brillegeit Gang.

Last edited by jean-paul; 23rd September 2012 at 09:03 PM.
  Reply With Quote
Old 26th September 2012, 06:37 PM   #10
diyAudio Member
 
Join Date: Oct 2004
Location: Aalborg, Denmark
Quote:
Originally Posted by jean-paul View Post
. If you are going to use connector blocks for the outputs (if only for testing) the pads for those must be moved somewhat to the left or you will have to mount the PCB with only 3 screws
There is enough room for the connector blocks, no worries, done many boards before and I know what I am doing.
  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
Bragi, WM8804/ES9023 DAC Neutrality Digital Line Level 9 22nd September 2012 11:10 AM
FS: Alps RK27 motorised volume pot with remote controller PCB ready to fit in amp rabbitz Swap Meet 3 8th September 2004 03:09 PM


New To Site? Need Help?

All times are GMT. The time now is 04:46 AM.


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