Soekris 's DAC implementations - Page 2 - diyAudio
Go Back   Home > Forums > Source & Line > Digital Line Level
Home Forums Rules Articles diyAudio Store Gallery Wiki Blogs Register Donations FAQ Calendar Search Today's Posts Mark Forums Read

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 January 2015, 06:56 PM   #11
pooge is offline pooge  United States
diyAudio Member
 
Join Date: May 2003
Location: Northern Va.
Quote:
Originally Posted by Eldam View Post
Hi,

A thread to know how to implement : volume control, filter, casing, shielding, powersupply, etc for the discrete R2R DAC maid by Soekris,

Feel free to ask and answer.

Regards

Eldam
It would be helpful if you edited post #1 with a link to the Soekris thread.
  Reply With Quote
Old 14th January 2015, 11:54 PM   #12
leehan is offline leehan  United Kingdom
diyAudio Member
 
Join Date: Jun 2010
Location: Kent, UK
To those who are thinking regulating the voltage instead of just feeding it directly with the suggested transformer by Soekris:

Do you think there is a weakness in the power supply section already built-in the module? If so, doesn't this worry you about rest of the design?

Or do you think the more regulation the better?

If one would like the keep things as simple as possible, is the following configuration too simple to hear benefits of R2R architecure?

1. DAC module
2. Toroidal transformer
3. Amareno USB powered USB-to-I2S module

(I'm asking with all my due respect for you experienced diy'ers, and just trying to understand the motivation.)

Cheers.
  Reply With Quote
Old 15th January 2015, 07:56 AM   #13
Hennie is offline Hennie  South Africa
diyAudio Member
 
Join Date: Nov 2004
Location: Pretoria
Subscribed
  Reply With Quote
Old 15th January 2015, 09:26 AM   #14
diyAudio Member
 
Join Date: May 2005
Location: Melbourne
Blog Entries: 1
Quote:
Originally Posted by leehan View Post
To those who are thinking regulating the voltage instead of just feeding it directly with the suggested transformer by Soekris:

Do you think there is a weakness in the power supply section already built-in the module? If so, doesn't this worry you about rest of the design?

Or do you think the more regulation the better?

If one would like the keep things as simple as possible, is the following configuration too simple to hear benefits of R2R architecure?

1. DAC module
2. Toroidal transformer
3. Amareno USB powered USB-to-I2S module

(I'm asking with all my due respect for you experienced diy'ers, and just trying to understand the motivation.)

Cheers.
Søren's posts indicate that he looked at the requirements of specific sections of the DAC and then designed local regulation and filtering to allow the DAC to meet the performance specs he was aiming for.

There are low noise regulators used around the board. The references for the R2R ladders are first regulated to 5V with low noise regulators then to 4V using precision low noise op-amps, then filtered and buffered for each channel and rail.

Extra regulation might help somewhat but from what I've read and understand Søren has taken great care with the areas he has deemed critical to performance. The DAC should perform well with the AC hooked up directly. If you wanted to use a DC supply something using LM3x7's is going to be more than adequate.

The rest of the DAC appears to be designed with equal care, and Søren's 14+ years of experience designing embedded computer motherboards is apparent in the quality of the layout.

In terms of hooking up your list looks fine to me, I'm planning something similar but might add a coax SPDIF input to the list.

The design integrates isolators on the I2S inputs and a FIFO and reclocking for jitter reduction which removes the need for extra boards for these purposes.
  Reply With Quote
Old 15th January 2015, 09:58 AM   #15
leehan is offline leehan  United Kingdom
diyAudio Member
 
Join Date: Jun 2010
Location: Kent, UK
Quote:
Originally Posted by spzzzzkt View Post
In terms of hooking up your list looks fine to me, I'm planning something similar but might add a coax SPDIF input to the list.

The design integrates isolators on the I2S inputs and a FIFO and reclocking for jitter reduction which removes the need for extra boards for these purposes.
Indeed.

I'm thinking of adding a coax SPDIF input as well because every device other than my computer has an optical output. An external optical to coaxial converter may feed the coaxial input. Or another little diy project with multiple user switchable optical inputs may be easier to use and keep the DAC box uncluttered. Is adding a SPDIF input just a matter of a coaxial terminal wired to the DAC module?
  Reply With Quote
Old 15th January 2015, 10:21 AM   #16
diyAudio Member
 
Join Date: May 2005
Location: Melbourne
Blog Entries: 1
Quote:
Originally Posted by leehan View Post
Indeed.

I'm thinking of adding a coax SPDIF input as well because every device other than my computer has an optical output. An external optical to coaxial converter may feed the coaxial input. Or another little diy project with multiple user switchable optical inputs may be easier to use and keep the DAC box uncluttered. Is adding a SPDIF input just a matter of a coaxial terminal wired to the DAC module?
Until the documentation is ready it's bit of guess work on the exact details.

I suspect RCA/BNC -> pulse transformer -> DAC will be the way to go for coax SPDIF. There isn't too much required apart from a couple of capacitors and a resistor or two so it should be easy to build on perf board or even point to point. There are more complicated ways of doing this - Jocko's SPDIF receiver is one but requires power as it uses an IC in addition to a pulse transformer.

TOSLINK is pretty simple as the receiver only requires a power supply plus resistor and capacitor to make it work.

Apparently there will be a means of switching inputs, so if you don't need AES/EBU or coax SPDIF you could potentially dedicate two or three inputs to TOSLINK.
  Reply With Quote
Old 15th January 2015, 10:42 AM   #17
leehan is offline leehan  United Kingdom
diyAudio Member
 
Join Date: Jun 2010
Location: Kent, UK
Quote:
Originally Posted by spzzzzkt View Post
I suspect RCA/BNC -> pulse transformer -> DAC will be the way to go for coax SPDIF. There isn't too much required apart from a couple of capacitors and a resistor or two so it should be easy to build on perf board or even point to point. There are more complicated ways of doing this - Jocko's SPDIF receiver is one but requires power as it uses an IC in addition to a pulse transformer.

TOSLINK is pretty simple as the receiver only requires a power supply plus resistor and capacitor to make it work.

Apparently there will be a means of switching inputs, so if you don't need AES/EBU or coax SPDIF you could potentially dedicate two or three inputs to TOSLINK.
Excellent, thank you.
  Reply With Quote
Old 15th January 2015, 02:32 PM   #18
Eldam is offline Eldam  France
Banned
 
Join Date: Sep 2012
Location: France
if a 2 x 9 V AC measured at 11.3 at the output :

I have after the drop of diodes bridge : 9.6 VDC (11.3 -1.6 diodes) after the cap.

So 13.6 VDC unloaded or is it 13.6 VDC loaded ? (9.6V x 1.41).

Sorry if already asked in the main thread, I inderstand fast but one have to explain me longly !

My thought : just maid a non regulated Pi to save the first caps of the dac which are maybe not Long Life ! And secondly : a cap // on the second cap of the Pi before the DAC can help to Taylor a little the subjective sound result in relation to each system ?!

I think to : 2x9V + Snubber + diodes + Panasonic FR 25V/2000 uF (both LL and low esr) then a common smt chocke 47 uH + FR 25V/2000 uF (// with 220 uF to taylor slightly the sound : Black Gate, other polymer, etc !).

Is my calcul good ?

In the other way I ask myself if all the time constants calculated by Soren are just good at it is and maid firstly for the 7 or 8 V AC traffo feeding directly the DAC ?

Soren or others if you have the patience, please ?

Last edited by Eldam; 15th January 2015 at 03:01 PM.
  Reply With Quote
Old 15th January 2015, 03:38 PM   #19
soekris is offline soekris  Denmark
diyAudio Member
 
Join Date: Jun 2009
Quote:
Originally Posted by Eldam View Post
if a 2 x 9 V AC measured at 11.3 at the output :

I have after the drop of diodes bridge : 9.6 VDC (11.3 -1.6 diodes) after the cap.

So 13.6 VDC unloaded or is it 13.6 VDC loaded ? (9.6V x 1.41).

Sorry if already asked in the main thread, I inderstand fast but one have to explain me longly !

My thought : just maid a non regulated Pi to save the first caps of the dac which are maybe not Long Life ! And secondly : a cap // on the second cap of the Pi before the DAC can help to Taylor a little the subjective sound result in relation to each system ?!

I think to : 2x9V + Snubber + diodes + Panasonic FR 25V/2000 uF (both LL and low esr) then a common smt chocke 47 uH + FR 25V/2000 uF (// with 220 uF to taylor slightly the sound : Black Gate, other polymer, etc !).

Is my calcul good ?

In the other way I ask myself if all the time constants calculated by Soren are just good at it is and maid firstly for the 7 or 8 V AC traffo feeding directly the DAC ?

Soren or others if you have the patience, please ?
Remember that AC voltage is specified as RMS and are sinus formed, so you always need to multiply by sqrt 2 to get Peak voltage, which will then go though bridge and loaded on the capacitor....

So if you measure 11.3V AC unloaded that would be 15.98V Peak...

So if you have an additional regular bridge rectifier then a 9V AC trafo is probably fine, but you might also want to add a small series resistor to get the voltage down a little....
__________________
Søren
  Reply With Quote
Old 15th January 2015, 04:00 PM   #20
Eldam is offline Eldam  France
Banned
 
Join Date: Sep 2012
Location: France
Thank you so much, My understanding is better now (so I don't keep the drop of 1.6 V due to the bridge of the DC PS I want to make in the calcul for the ending peak to peak).

Ok will swap the chocke of the Pi by a 2 W resistor of the good value to have less than 15V peak to peak (around 9 max VDC to have peak to peak something like 12.5 VDC max as advised).

So the traffo is a R-core 9V/30 VA (that's why I have only 11.3 v AC on the secondaries).

Does the time constant should be keeped with such DC PS before your DAC or do you advise better a standalone 7-8 VAC torroid traffo, despite the rude pulsed current on the first polymers of your DAC !

Two cents of me, it will sounding the same in both case with equal result ?
  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
The DAC "do you have experience with this dac", Best diy dac for the money? murphythecat8 Construction Tips 9 17th March 2014 07:30 AM
WTB V2.6 PCB for ES9023 / WM8804 S/PDIF DAC –SUBBU DAC grufti Swap Meet 0 26th November 2012 05:51 PM
Ebay dac with: DAC TDA1541, AD1865, AD1955, PCM63, & CS4398! sharpi31 Digital Line Level 2 10th January 2011 07:03 AM
Sabre DAC implementations SunRa Digital Line Level 1 18th December 2010 04:35 PM
diyclub.biz DAC-38, DAC-60, DAC-68. Anybody heard? TonyDasilva Digital Line Level 21 13th April 2009 05:10 PM


New To Site? Need Help?

All times are GMT. The time now is 03:38 PM.


vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2017 DragonByte Technologies Ltd.
Copyright ©1999-2017 diyAudio

Content Relevant URLs by vBSEO 3.3.2
Wiki