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 14th December 2012, 08:17 AM   #611
acko is offline acko  Australia
diyAudio Member
 
Join Date: Jan 2008
Location: Sydney, Australia
Default AKL Series

Quote:
Originally Posted by Nikola Krivorov View Post
Will it be offered for sale?
Yes, it will be. Finalising design... Still tossing between the easy to get TI FFs (3ns) or the PotSemi ones (<2ns)
__________________
AckoDAC Project
  Reply With Quote
Old 14th December 2012, 07:03 PM   #612
acko is offline acko  Australia
diyAudio Member
 
Join Date: Jan 2008
Location: Sydney, Australia
Standard package as part of the new AKU series.
Versions for Hiface, WaveIO, EXA2UI and Amanero
__________________
AckoDAC Project

Last edited by acko; 14th December 2012 at 07:11 PM.
  Reply With Quote
Old 15th December 2012, 08:55 AM   #613
glt is offline glt  United States
diyAudio Member
 
Join Date: Oct 2004
Asynchronous re-clocking...
There was a discussion precisely on this method of reclocking over at my blog a few days ago. I concluded that because the clock speed is much higher than the sample rate, the reclocking is always bit-perfect.

However, the width of the pulses (eg bitclock) will be changing, modulated by the 100MHz clock. What are your thoughts on this?


Quote:
Originally Posted by acko View Post
Folks,

This is another attempt to get the EX2UI board to work with the Turbo Clock (AKX701) unit. (In my previous post I highlighted some difficulties)

The EXA unit has a FIFO-buffer + dual clock on a compact board, all great for jitter elimination. However, the I2S output signals go through isolator chips (IL715) and thereby gets slightly degraded (jitter-wise). The reclocker module (AKL series) serves to clean up the I2s signals from the EXA unit. The reclocked + bufffered outputs are on w.fl coax headers to match the DAC module (AKD12P). Pin headers from the AKL connect directly to the EXA2UI output terminal block as shown.

The re-clock Flip-flops are clocked by the same MCLK as that of the DAC (100M). Used this way results in Async Re-Clocking.

I have also added Clock isolator on board so that the divided slave clocks from the AKX701 Clock module can be safely piped into the EX2UI for Sychronous Re-Clocking. As the reclock MCLK freq is much higher (100M) than the transport clocks (25M), I am hoping that this 'Turbo' reclocking technique will be able handle higher sample rates without problems.

Also added on board is a Sample Rate DAQ and transmitter (I2C comms). The MCU can read Fs direct from the transport and display accordingly.

Shown is 2CH version. 8CH with AKD18 DAC, similarly.
Other tranports can similarly benefit from this arrangment and I will be rolling these out soon.
__________________
www.hifiduino.wordpress.com
  Reply With Quote
Old 15th December 2012, 10:13 PM   #614
acko is offline acko  Australia
diyAudio Member
 
Join Date: Jan 2008
Location: Sydney, Australia
Default Async Re-Clocking

Quote:
Originally Posted by glt View Post
Asynchronous re-clocking...
There was a discussion precisely on this method of reclocking over at my blog a few days ago. I concluded that because the clock speed is much higher than the sample rate, the reclocking is always bit-perfect.

However, the width of the pulses (eg bitclock) will be changing, modulated by the 100MHz clock. What are your thoughts on this?
Thanks GLT, very interesting convergence of ideas from different parties
You have also nailed it nicely in your blog that I only vaguely managed to imagine! Again the scope of my plan is Sync Re-Clocking really with the AKX701 that is easy to frame and analyse the timing. It then became obvious if a simple DAC MLCK is used and no transport interaction then it defaults to ASync Re-Clocking. ASync re-clocking has been used since the beginning of times e.g. Typical Application


I haven't analysed the detailed timing but would assume at 100MHz reclock on say, 500KHz Fs bitclock would not cause problems even if not synchronised. Also, if it has worked for the above implementation then we are assured?

BTW, all lines BCK, LRCK and SDA are re-clocked for my version.

Any further thoughts most welcome
__________________
AckoDAC Project
  Reply With Quote
Old 15th December 2012, 11:00 PM   #615
acko is offline acko  Australia
diyAudio Member
 
Join Date: Jan 2008
Location: Sydney, Australia
.... and PotSemi FFs
__________________
AckoDAC Project
  Reply With Quote
Old 16th December 2012, 12:55 AM   #616
glt is offline glt  United States
diyAudio Member
 
Join Date: Oct 2004
Quote:
Originally Posted by acko View Post
Thanks GLT, very interesting convergence of ideas from different parties
...ASync re-clocking has been used since the beginning of times e.g. Typical Application

...

BTW, all lines BCK, LRCK and SDA are re-clocked for my version.

Any further thoughts most welcome
You are right! This stuff is ancient. Thanks for the link...
__________________
www.hifiduino.wordpress.com
  Reply With Quote
Old 16th December 2012, 01:28 AM   #617
acko is offline acko  Australia
diyAudio Member
 
Join Date: Jan 2008
Location: Sydney, Australia
Default Async Re-Clock

Ancient?

... there is something similar on the new TPA BIII
__________________
AckoDAC Project
  Reply With Quote
Old 16th December 2012, 02:21 AM   #618
Bunpei is offline Bunpei  Japan
diyAudio Member
 
Join Date: Aug 2008
Quote:
Originally Posted by acko View Post
However, the I2S output signals go through isolator chips (IL715) and thereby gets slightly degraded (jitter-wise).
exa065 said on his post in exaDevices thread,
exaU2I - Multi-Channel Asynchronous USB to I2S Interface

Quote:
Originally Posted by exa065 View Post
... Note to the exaU2I users with ES9018 DACs - don't bother removing the GMRs - in your case removing the GMRs won't make any difference. ES9018 takes care of the GMR jitter, and replacing the GMR isolation with optical isolation will not present a rational improvement. ...
How do you feel about his notice?
  Reply With Quote
Old 16th December 2012, 04:32 AM   #619
acko is offline acko  Australia
diyAudio Member
 
Join Date: Jan 2008
Location: Sydney, Australia
Quote:
Originally Posted by Bunpei View Post
exa065 said on his post in exaDevices thread,
exaU2I - Multi-Channel Asynchronous USB to I2S Interface

..
ES9018 takes care of the GMR jitter
..
How do you feel about his notice?
Thanks for the feedback

Yes, the EXA sound great of its own with this DAC but we need to test this case or see if further improvements can be made (Async mode). This idea is to reduce or eliminate jitter altogether before reaching the DAC so that the DAC does the final clean up to make it sound even better.

It will be fairly easy to do A/B comparison with my own DAC. There is no re-clocker circuit on the DAC board itself so we can insert an external re-clocker board (like the AKL module) between the DAC and the EXA unit. No mods
__________________
AckoDAC Project
  Reply With Quote
Old 16th December 2012, 07:48 AM   #620
Bunpei is offline Bunpei  Japan
diyAudio Member
 
Join Date: Aug 2008
Dear acko,

I am much satisfied with your profound answer!

If you want a better result on USB, I'd like to recommend the use of this optical isolator.
exaU2I - Multi-Channel Asynchronous USB to I2S Interface
  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
WM8816 based pre-amp panson_hk Chip Amps 13 22nd May 2009 02:16 PM
DIY ESL III (based on an ER Audio Kit) jasonlky Planars & Exotics 7 23rd January 2008 07:09 AM
UCD based amp oldmaelstrom2 Class D 3 27th June 2007 10:10 AM


New To Site? Need Help?

All times are GMT. The time now is 11:05 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