OLD THREAD DAC End by Andrea Ciuffoli - Page 111 - diyAudio
Go Back   Home > Forums > Commercial Sector > Vendor Forums > Quanghao Audio Design

Quanghao Audio Design Quanghao Audio Design is a producer of DIY Audiophile Kits and PCB boards, selected from many listening tests!

Reply
 
Thread Tools Search this Thread
Old 15th March 2010, 11:01 AM   #1101
adamus is offline adamus  United Kingdom
diyAudio Member
 
Join Date: Apr 2008
*with LED bias* its more natural than the dacmagic, the depth of the soundstage is greater and it makes the dacmagic sound a bit false (mids / highs too forward).

The dacmagic is brighter, so detail is more in your face, but its all there with the dacend, and i prefer the natural quality.

For me, without the led bias i found the bass to loose. IT was too warm and cuddly and a little confused in complex bass passages.

I have had a play with a css, and am unsure so far as to whether i like it or not. It tightens the bass further, but you do loose some of that lovely valve sound (for the scientists you probably read that as 'valve distortion'). Its more clinical and detailed, but not sure if i like it or not yet. The CSS also needs a lot of heatsinking, its dropping a lot of volts!
  Reply With Quote
Old 15th March 2010, 11:11 AM   #1102
tassosk is offline tassosk  Greece
diyAudio Member
 
Join Date: Sep 2008
Quote:
Originally Posted by adamus View Post
*with LED bias* its more natural than the dacmagic, the depth of the soundstage is greater and it makes the dacmagic sound a bit false (mids / highs too forward).

The dacmagic is brighter, so detail is more in your face, but its all there with the dacend, and i prefer the natural quality.

For me, without the led bias i found the bass to loose. IT was too warm and cuddly and a little confused in complex bass passages.

I have had a play with a css, and am unsure so far as to whether i like it or not. It tightens the bass further, but you do loose some of that lovely valve sound (for the scientists you probably read that as 'valve distortion'). Its more clinical and detailed, but not sure if i like it or not yet. The CSS also needs a lot of heatsinking, its dropping a lot of volts!
Thanks for the feedback.
Appart the output stage mods, we also have to consider the Salas suggestion regarding the bypass of the 431, if anyone has the knowledge to apply it correctly.
  Reply With Quote
Old 15th March 2010, 11:12 AM   #1103
adamus is offline adamus  United Kingdom
diyAudio Member
 
Join Date: Apr 2008
not sure, its probably not something i will be trying. on the scope there is more noise after the tl431's, so i can see why salas is suggesting it
  Reply With Quote
Old 15th March 2010, 02:29 PM   #1104
diyAudio Member
 
apelizzo's Avatar
 
Join Date: Sep 2006
Quote:
Originally Posted by CustomHT View Post
So where to now??

Are you gonna try and upgrade this dac or I/V tube stage to improve its performance?
First I'm gonna cross the two DACs. New DAC with old tube stage, and old DAC with new tube stage. This way I can identify where is the major issue.

Adamus, if you can help me with your experience: my friends told me that the new DAC comparing to other two already has less bass. If I apply your mod am I going to loose more bass?

Tell me if you need to know all the parts in the circuit. Sometime oscon are responsible of bass.

Do you use the passive filter before I/V?

Last edited by apelizzo; 15th March 2010 at 02:31 PM.
  Reply With Quote
Old 15th March 2010, 02:33 PM   #1105
diyAudio Member
 
apelizzo's Avatar
 
Join Date: Sep 2006
Quote:
Originally Posted by adamus View Post
do the led bias mod, it makes a very good impact.

cathode bypass caps to my ears sound a little confused and muddy.

Replace the anode resistors with a CSS or gyrator (the later i have not tried). 7.5ma is a little too low on the 5687's, 12ma + is a good idea to be linear.

Good point Adamus, I feel the distortion is also a little high.
  Reply With Quote
Old 15th March 2010, 02:38 PM   #1106
adamus is offline adamus  United Kingdom
diyAudio Member
 
Join Date: Apr 2008
Quote:
Originally Posted by apelizzo View Post
First I'm gonna cross the two DACs. New DAC with old tube stage, and old DAC with new tube stage. This way I can identify where is the major issue.

Adamus, if you can help me with your experience: my friends told me that the new DAC comparing to other two already has less bass. If I apply your mod am I going to loose more bass?

Tell me if you need to know all the parts in the circuit. Sometime oscon are responsible of bass.

Do you use the passive filter before I/V?
Passive filter installed (bourns 120uf)

you wont loose bass, it will be more controlled and the low mids will be better resolved, i found it 'wooly' messy if you like pre mod.

Everything is was slightly better resolved for me. i find a lto of people describe wooly bass + low mid as warmth, so you will loose a little 'warmth'.
  Reply With Quote
Old 15th March 2010, 02:46 PM   #1107
diyAudio Member
 
apelizzo's Avatar
 
Join Date: Sep 2006
Default Low distortion tube stage

Tube stage with 5670 or russian 6N23P designed and used in my old DAC considered having better sound. Gain to be adjusted.
Also added shunt tube regulator on +/-85V
Attached Images
File Type: jpg Tube stage1.jpg (122.3 KB, 388 views)

Last edited by apelizzo; 15th March 2010 at 03:03 PM.
  Reply With Quote
Old 15th March 2010, 02:53 PM   #1108
diyAudio Member
 
Join Date: Sep 2009
Location: Vietnam
Blog Entries: 2
Send a message via Yahoo to quanghao Send a message via Skype™ to quanghao
Quote:
Originally Posted by apelizzo View Post
Tube stage with 5670 or russian 6N23P I designed and used in my old DAC considered having better sound. Gain to be adjusted.
Also added shunt tube regulator on +/-85V
My old DAC? what chip do you use???
__________________
Group buy DAC-END R (ES9018) full assembled board
update 06/14/2013 :http://www.audiodesignguide.com/DAC32/index2.html
  Reply With Quote
Old 15th March 2010, 02:56 PM   #1109
diyAudio Member
 
apelizzo's Avatar
 
Join Date: Sep 2006
Quote:
Originally Posted by quanghao View Post
My old DAC? what chip do you use???
Exactly the same setup. It's the DAC End with transformer but instead of expensive transformers I've done a tube stage.

Last edited by apelizzo; 15th March 2010 at 03:02 PM.
  Reply With Quote
Old 15th March 2010, 02:59 PM   #1110
Pocoyo is offline Pocoyo  Indonesia
diyAudio Member
 
Pocoyo's Avatar
 
Join Date: Jan 2007
Location: Indonesia
Tamura ???
  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
OLD THREAD Hi-end phono preamplifier by Andrea Ciuffoli quanghao Quanghao Audio Design 406 27th October 2014 04:40 AM
Cleo: End to End 24bit 192khz USB DAC with tube output bcherry DIY HiFi Supply 7 4th July 2010 12:15 AM
The DAC End 2 by Andrea Ciuffoli pcb + most parts... prooptiki Swap Meet 7 31st May 2010 03:21 AM
Custom designed transformer for Andrea Ciuffoli 6c33c OTL AMP.... zxcxz Tubes / Valves 2 10th July 2009 05:14 PM
Andrea Ciuffoli Mosfet Amp DieterD Solid State 16 24th December 2001 06:56 AM


New To Site? Need Help?

All times are GMT. The time now is 05:29 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