A NOS 192/24 DAC with the PCM1794 (and WaveIO USB input) - Page 29 - diyAudio
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 3rd April 2013, 04:21 PM   #281
diyAudio Member
 
Join Date: Feb 2013
Quote:
Originally Posted by tuyen View Post
Curious to know subjective differences in sound running choke loaded psu / tube rectified psu compares to the standard psu kit offered by Doede? Also Supersurfer, noticed you are using pair of red black gates on the psu instead of the nichicons. Much diff?

Cheers
I didn't compare directly with the nichicons in the dddac supply. The black gates were lying around and I had some good results with these in super E-cap ( they are non-polars) configuration with a previous dac, so I just put them in.
I have not tweaked with other things because I am still optimising with the shunt regulators and sowters, also some salas shunt boards are lying around that I will try first.

The supply and dac boards are difficult to desolder because of the big ground plane (it dissipates all the heat of the soldering iron) so exchanging components is not an easy task. Even when I use a desoldering iron with suction pump

Btw: The nichicons muse that Doede selected are pretty good also!
  Reply With Quote
Old 3rd April 2013, 08:09 PM   #282
diyAudio Member
 
Join Date: Sep 2004
Location: Goor
Default building project on Audio Creative

Hi Doede,

There is a nice building project of your PCM1794 DAC on Audio-Creative:
Lot's of pic's as well

We gaan verder met Deel 2 van de bouw van de DDDAC 1794 NOS DIY DAC waarin we gedetailleerd ingaan op de bouw er van en mogelijke tweaks. - Audio-Creative
  Reply With Quote
Old 4th April 2013, 01:34 AM   #283
diyAudio Member
 
Join Date: May 2011
Do the output capacitors have to be 2.2uf? Can I use 0.1uf for that?
  Reply With Quote
Old 4th April 2013, 01:39 AM   #284
dogears is offline dogears  Philippines
diyAudio Member
 
Join Date: Feb 2004
Location: Philippines
Secured a Benchmark DAC-1 already but item is still in Singapore :P
  Reply With Quote
Old 4th April 2013, 03:00 AM   #285
bravi is offline bravi  New Zealand
diyAudio Member
 
Join Date: Mar 2004
Location: Wellington, New Zealand
Default Choke loaded supply

Hi Supersurfer,

Ref your question whether choke loading is necessary with a regulated supply. The basic approach I have found useful even for solid state is to get the raw supply ripple as smooth as possible. With the choke loaded supply I have used, the out put ripple in the raw supply is in the mv range and is a smooth sine wave of 100hz frequency(Checked this on an oscilloscope). Without choke loading the sharp charging currents have harmonics which you can only reduce with a regulator, not eliminate. This does impact sound quality.

An example of my experience.When upgrading my Revox B77 open reel tape machine, I used a Jung type super regulator (developed by AL Weekes) to replace a 7820 type regulator. This step resulted in a big improvement in sound. When I added a Gyrator to smoothen the ripple from the raw supply, another jump up in the quality. Finally, last week I added a common mode choke after the raw supply as I had concerns about rfi pollution of mains in my location. This resulted in another huge jump in sound quality. Now. listening to 4 track reel tapes from the 60s and 70s, I am able to realise the inherent high quality of recording in some them, when listening through headphones. Did not expect this to happen. Hence, my approach re PSU.

To summarise, a well smoothed raw supply with only 100hz ripple in the raw supply may enable the regulator to perform at its optimium level and help in obtaining the best possible sound from the DAC.

Sorry for the long message. Hope, this is of assistance.

Cheers!
  Reply With Quote
Old 4th April 2013, 05:18 AM   #286
dddac is offline dddac  Germany
diyAudio Member
 
Join Date: Jul 2003
Location: Wiesbaden
Quote:
Originally Posted by lxiaob View Post
Do the output capacitors have to be 2.2uf? Can I use 0.1uf for that?
That is covered on my Website...

Output Options
__________________
www.dddac.com
Happy listening and building
  Reply With Quote
Old 4th April 2013, 05:21 AM   #287
dddac is offline dddac  Germany
diyAudio Member
 
Join Date: Jul 2003
Location: Wiesbaden
Quote:
Originally Posted by bravi View Post
Hi Supersurfer,

Ref your question whether choke loading is necessary with a regulated supply. The basic approach I have found useful even for solid state is to get the raw supply ripple as smooth as possible. With the choke loaded supply I have used, the out put ripple in the raw supply is in the mv range and is a smooth sine wave of 100hz frequency(Checked this on an oscilloscope). Without choke loading the sharp charging currents have harmonics which you can only reduce with a regulator, not eliminate. This does impact sound quality.

An example of my experience.When upgrading my Revox B77 open reel tape machine, I used a Jung type super regulator (developed by AL Weekes) to replace a 7820 type regulator. This step resulted in a big improvement in sound. When I added a Gyrator to smoothen the ripple from the raw supply, another jump up in the quality. Finally, last week I added a common mode choke after the raw supply as I had concerns about rfi pollution of mains in my location. This resulted in another huge jump in sound quality. Now. listening to 4 track reel tapes from the 60s and 70s, I am able to realise the inherent high quality of recording in some them, when listening through headphones. Did not expect this to happen. Hence, my approach re PSU.

To summarise, a well smoothed raw supply with only 100hz ripple in the raw supply may enable the regulator to perform at its optimium level and help in obtaining the best possible sound from the DAC.

Sorry for the long message. Hope, this is of assistance.

Cheers!
Hi Bravi, fully agree, the Regulation does it Thing and less garbage in, is less garbage out
__________________
www.dddac.com
Happy listening and building
  Reply With Quote
Old 4th April 2013, 05:22 AM   #288
dddac is offline dddac  Germany
diyAudio Member
 
Join Date: Jul 2003
Location: Wiesbaden
Quote:
Originally Posted by dr.knibbeling View Post
Hi Doede,

There is a nice building project of your PCM1794 DAC on Audio-Creative:
Lot's of pic's as well

We gaan verder met Deel 2 van de bouw van de DDDAC 1794 NOS DIY DAC waarin we gedetailleerd ingaan op de bouw er van en mogelijke tweaks. - Audio-Creative
Indeed, great article. Even if you don't speak dutch, the many Pictures are telling a good Story as well!
__________________
www.dddac.com
Happy listening and building
  Reply With Quote
Old 4th April 2013, 05:19 PM   #289
diyAudio Member
 
Join Date: Feb 2013
Hi Bravi,

I understand your approach. I have used a shunt regulator in a tube amp that had a tube rectifier and two chokes in front of the shunt regulator. This worked fine except for one thing, the power mosfets were very sucseptable to voltage peaks and I got tired of exchanging them after every break down. So I finally got rid of the shunt regulator and used a simple unregulated supply with: cap,choke,cap,choke,cap,choke,cap. This worked perfectly and I never had the urge to use a supply regulator again.

To put this in perspective; the amp was a single ended type so everything that comes out of the supply will be amplified and heard.

This got me wondering if it would not be an idea to use an unregulated choke supply on the dac. The current draw would probably be fairly steady because the dac chips run in balanced mode.

Can you confirm this Doede?

Selection of shottky diodes and use of resistors around the diodes will also help in stopping inrush peaks. However not as effevtively as a choke, but it is much more compact and cheap.

Regards,

Last edited by Supersurfer; 4th April 2013 at 05:26 PM.
  Reply With Quote
Old 4th April 2013, 05:38 PM   #290
dddac is offline dddac  Germany
diyAudio Member
 
Join Date: Jul 2003
Location: Wiesbaden
Quote:
Originally Posted by Supersurfer View Post
Hi Bravi,

I understand your approach. I have used a shunt regulator in a tube amp that had a tube rectifier and two chokes in front of the shunt regulator. This worked fine except for one thing, the power mosfets were very sucseptable to voltage peaks and I got tired of exchanging them after every break down. So I finally got rid of the shunt regulator and used a simple unregulated supply with: cap,choke,cap,choke,cap,choke,cap. This worked perfectly and I never had the urge to use a supply regulator again.

To put this in perspective; the amp was a single ended type so everything that comes out of the supply will be amplified and heard.

This got me wondering if it would not be an idea to use an unregulated choke supply on the dac. The current draw would probably be fairly steady because the dac chips run in balanced mode.

Can you confirm this Doede?

Selection of shottky diodes and use of resistors around the diodes will also help in stopping inrush peaks. However not as effevtively as a choke, but it is much more compact and cheap.

Regards,
yes, I can confirm... current is very constant, just varying like 5-10mA per Board when 44 or 192 is playing or no Signal is applied...
__________________
www.dddac.com
Happy listening and building
  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
FS: Audio Widget (modified) Async USB DAC 24/192 ESS 9023 headphone friendly ASIO KS 2A3SET Swap Meet 5 15th August 2012 04:52 AM
Show my PCM1794 DAC TSOLINK + COAX + USB input, Line and headphone AMP output AWaudio Vendor's Bazaar 3 2nd January 2012 12:44 PM
GodDAC - 192/24 USB DAC BizonGod Digital Source 36 30th June 2011 03:16 PM
24 bit/192 kHz via USB? gentlevoice Everything Else 3 22nd December 2008 06:24 AM


New To Site? Need Help?

All times are GMT. The time now is 10:00 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