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.

AK4499 DAC Design
AK4499 DAC Design
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 November 2019, 05:38 PM   #1
adam1016 is offline adam1016  United States
diyAudio Member
 
Join Date: Jan 2016
Location: Chicago, IL
Default AK4499 DAC Design

Hello,
I wanted to design an open source and open hardware DAC around the AK4499 DAC Chip that other members are free to copy, reuse, share, and remix. I previously started a thread for doing this around the ES9038, which piqued my interest at first, but have found that the restrictions that ESS places on their documents go against the values of this project. I am moving forward with the AK4499 As the DAC chip, either using another AK chip or the WM8805. Planning on using either an Op-amp or JFET based I-V stage, and separate LDO's for each of the power supplies on the chip. Unfortunately haven't seen the Eval Board schematics, would appreciate if somebody could post them.
  Reply With Quote
Old 21st November 2019, 10:51 PM   #2
adam1016 is offline adam1016  United States
diyAudio Member
 
Join Date: Jan 2016
Location: Chicago, IL
Got my hands on the eval board schematics, moving forward with this design. A couple choices right off the bat:

I will be using two AK4499 Chips in dual Mono, starting out with an SE Class A output stage, and maybe going balanced in the future. I will be using software control mode, using a microcontroller to control both chips. I think that I will use an XMOS chip, and crystek oscillators.
  Reply With Quote
Old 21st November 2019, 10:56 PM   #3
Markw4 is offline Markw4  United States
diyAudio Member
 
Join Date: Jul 2016
Location: California
Dual AK4499 is totally not needed, unless perhaps 8-channels is a must have. Its hard enough to do a good job with one AK4499. Due to the complexity of AK4499 output powering (dac chip and I/V), cost would be expected to go up quite a bit for extra channels.

Also, opamp I/V conversion is probably the only realistic way to go. Could be followed with class A after that. Otherwise, you would probably be increasing distortion by way of trying to reduce it.

Not clear that Crystek clocks are actually better than NDK SDA series, if the implementation is done properly. Some people prefer the sound of NDK.

Regarding SPDIF receivers with master clock recovery, SPDIF often tends to be jittery. Master clock recovery can work well under near-ideal conditions, but ASRC to a local crystal clock reference may be a more reliable choice. (That said, most if not all ASRC chips are limited to 2-channel processing.) AKM's ASRC solution, AK4137, also has the interesting ability to convert incoming PCM audio to DSD, up to and including DSD256. Of course a SPDIF receiver is still needed in some form. TI's SRC4392 is another good stereo ASRC with built-in SPDIF transceiver, but no DSD conversion.

Last edited by Markw4; 21st November 2019 at 11:26 PM.
  Reply With Quote
Old 21st November 2019, 11:42 PM   #4
Markw4 is offline Markw4  United States
diyAudio Member
 
Join Date: Jul 2016
Location: California
Adam,
Please let me know if I seem too critical or not tuned into what you want to do. I would be happy to keep quiet and let you have at it if that's what you want. Reason I brought up a lot of things in the last post was to stimulate thinking about design choices that I would want to think about before finalizing them, that's all.

Wishing the best for your project's success!

-Mark
  Reply With Quote
Old 22nd November 2019, 11:16 AM   #5
samoloko is online now samoloko  Bulgaria
diyAudio Member
 
Join Date: Jun 2006
you will produce pcb?
can you post shematic
please use true balanced output per channel using 4 chip outputs to corespond opamps (7 single opamps) not just 2 chip outputs like most do

Quote:
Originally Posted by adam1016 View Post
Got my hands on the eval board schematics, moving forward with this design. A couple choices right off the bat:

I will be using two AK4499 Chips in dual Mono, starting out with an SE Class A output stage, and maybe going balanced in the future. I will be using software control mode, using a microcontroller to control both chips. I think that I will use an XMOS chip, and crystek oscillators.

Last edited by samoloko; 22nd November 2019 at 11:19 AM.
  Reply With Quote
Old 22nd November 2019, 02:04 PM   #6
randytsuch is offline randytsuch
diyAudio Member
 
Join Date: Jan 2003
Location: LA
AK4499 DAC Design
IMHO, if you design pwb for a crystek its fairly easy to use a sot23-6 adapter to mount a NDK since NDK is smaller.
Probably not optimal, but options are always good.
__________________
My system is here
http://randytsuch-audio.blogspot.com/2005/10/my-system.html
  Reply With Quote
Old 25th November 2019, 12:28 AM   #7
adam1016 is offline adam1016  United States
diyAudio Member
 
Join Date: Jan 2016
Location: Chicago, IL
Thanks for all the feedback guys, I will be posting schematics here as they come along, definitely want to go for as modular of a design as possible, I'm leaning towards a backplane type system with a well-defined standard so that people can design their own modules, and hopefully have a completely open-source DAC ecosystem. I think I'm going to start with a single DAC chip per your comments @Markw4. I currently have an all-SE system, but plan on upgrading to balanced in the future and want this DAC to be capable of that. I'm still in the very early stages of this project, driven only by the desire to have a fully open-source state of the art future-proof dac, and here are the hurdles I expect to have to deal with:
- USB Input Stage
- Other Inputs ( Definitely SPDIF, maybe AES/EBU + Coax SPDIF )
- Clocking and clock distribution
- Power Supply
- I/V stage
- i2c control of the DAC chip

This is just at the schematic level, haven't even begun to approach layout yet. Let me know if you think I'm missing anything.
  Reply With Quote
Old 25th November 2019, 12:53 AM   #8
29285 is offline 29285  Europe
Account disabled at member's request
 
Join Date: Jan 2010
Do you know a reliable source for AK4499? They are not listed at Mouser and Digikey holds 0 samples.
  Reply With Quote
Old 25th November 2019, 01:00 AM   #9
Markw4 is offline Markw4  United States
diyAudio Member
 
Join Date: Jul 2016
Location: California
Adam, if you would like I could post a brief synopsis of what I have found with AK4499 so far. Turns out it can sound marvelous or mediocre depending on implementation details. Described most of it already in bits and pieces in other threads, but possibly helpful to summarize here.
  Reply With Quote
Old 25th November 2019, 01:08 AM   #10
Markw4 is offline Markw4  United States
diyAudio Member
 
Join Date: Jul 2016
Location: California
Quote:
Originally Posted by voltwide View Post
They are not listed at Mouser and Digikey holds 0 samples.
Digikey is the authorized evaluation board and dac chip retailer for this region. Don't know when they will have chips in stock, supposed to have been a few days ago. They have evaluation boards in small quantities from time to time. Guess AKM may be having chip production problems, don't know.
AKM's wholesale chip distributors also vary by region and are listed on AKM's website. They might be able to find out more than Digikey is saying.

Last edited by Markw4; 25th November 2019 at 01:11 AM.
  Reply With Quote

Reply


AK4499 DAC DesignHide 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
AK4479 or AK4499 DAC Kit???????? chinook9 Digital Line Level 21 18th November 2019 05:01 PM
Speaker Design : Comprehensive list of Recommended Design Tools Hearinspace Software Tools 22 14th December 2018 03:54 PM
Sound Design, a new book on innovative and interesting ideas in speaker design. Studio Au Multi-Way 3 8th April 2012 09:46 PM
Metronome style design for multiple drivers, a number of design questions mountainhick Multi-Way 5 28th January 2010 04:31 AM
Wilson Watt Puppy Clone Design - Design Review Please soundengine355 Multi-Way 8 15th August 2008 03:07 PM


New To Site? Need Help?

All times are GMT. The time now is 11:54 AM.


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