Da-capo issue (John W?) - Page 61 - 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 11th February 2010, 09:09 PM   #601
loris.p is offline loris.p  Italy
diyAudio Member
 
loris.p's Avatar
 
Join Date: Sep 2006
Location: Milano
Well I've changed the caps. Now I'm listening the DaCapo ( with the 24 bit filter) and everything works fine, no white noise, but this means nothing because the noise wasn't always present.. I'll leave it on for a couple of days and then I'll see.....

John, am I right if I say that using the clock-lock dic without the clock cable, there are of low level cliks-clips-cliks.....?

Loris
  Reply With Quote
Old 11th February 2010, 10:07 PM   #602
loris.p is offline loris.p  Italy
diyAudio Member
 
loris.p's Avatar
 
Join Date: Sep 2006
Location: Milano
John, just U and I online now....
here it's snowing a little.....

Last edited by loris.p; 11th February 2010 at 10:11 PM.
  Reply With Quote
Old 11th February 2010, 11:32 PM   #603
JohnW is offline JohnW  Hong Kong
diyAudio Member
 
JohnW's Avatar
 
Join Date: Jan 2004
Location: Discovery Bay, Prague, Paris...
Hi Loris,

Without clock cable - your lucky the Dacapo even produces audio - should indicate Lock, Low level clicks for sure - if not worst!

The Tranport and Dac are running without Sync. The Digitial Filter is "Soaking up" the timming differances - if you change to say 18 Bit Filter, you will find it will have a harder time...

Snowing here in CZ, does not stop. Bought a new car - had it less then a week (6 days) before a lady rear-end us while we waited at the lights...

John
__________________
Life shouldn't be taken too seriously as at the end of the day you will not come out of it alive anyway…
  Reply With Quote
Old 12th February 2010, 08:21 AM   #604
loris.p is offline loris.p  Italy
diyAudio Member
 
loris.p's Avatar
 
Join Date: Sep 2006
Location: Milano
Have you ever heard:
don't buy a new car while it's snowing?
  Reply With Quote
Old 12th February 2010, 10:38 AM   #605
JohnW is offline JohnW  Hong Kong
diyAudio Member
 
JohnW's Avatar
 
Join Date: Jan 2004
Location: Discovery Bay, Prague, Paris...
Hi Loris,

Now its my turn to say - I can't say if this is consolation..........

Hows the Dacapo?

John
__________________
Life shouldn't be taken too seriously as at the end of the day you will not come out of it alive anyway…
  Reply With Quote
Old 12th February 2010, 11:12 AM   #606
loris.p is offline loris.p  Italy
diyAudio Member
 
loris.p's Avatar
 
Join Date: Sep 2006
Location: Milano
Quote:
Originally Posted by JohnW View Post
Hi Loris,

Now its my turn to say - I can't say if this is consolation.........

John


I left the DaCapo hooked to a dvd/cd player ( optical link) in repeat mode all night long. This morning it was ok, no noise. Now I'm at work. I left it again on in repeat. I guess I'll leave it on for some day. I'll go home for lunch within an hour and I'll check it again.

Here's aPeachtree Idecco review:
http://www.avguide.com/review/peacht...7?src=Playback

BTW, if someone's interested I used Nichicon caps ( 8812519 at farnell)

Last edited by loris.p; 12th February 2010 at 11:15 AM.
  Reply With Quote
Old 12th February 2010, 01:35 PM   #607
diyAudio Member
 
aparatusonitus's Avatar
 
Join Date: Jan 2004
Location: Split, Croatia
Quote:
Originally Posted by JohnW View Post

You’re basically developing a "Dacapo" Discrete DAC. A couple of points:-

The SAA7350 Bitstream outputs need to be re-formatted to "Return to Zero" Bitstream coding; otherwise you will have very poor THD+N due to "incorrect Pulse energy". Basically you need to logic "And" with the Master Clock - you also need to generate the Negative Data Pulse.

+ Pulse = Clock High & Data High
- Pulse = Clock High & Data Low

So you only can have a resultant Pulse (+ or -) if the clock is high - resulting in half pulse integration energy per clock cycle - but without "Edge Rise/ Fall time errors (If Balanced) & Missing Edge" distortion.

After Generating the 2 Phases from the Bitstream, you should then Latch to a Master clock 16.9344MHz, (in the case of the SAA7350 the Bitstream modulator is operating at half MCLK) - to resynchronise to MCLK and remove the Phase Noise (Jitter) from the SAA7350 outputs & subsequent Bitstream reformatting circuit. If you use a Dual D-FF with Q and Q-, then you can end up with 4 "Dac Elements" that can be finally summed.

The Bitstream outputs of the SAA 7350 are very heavily jittered - if you simply integrate its outputs directly you will hear all kind of "Birdies" due to its internal processing "Jittering" the outputs (typically heard as the Music ramps up and down in Level – such as the start of a track).

These 2 reclocked Output Phases need to be individually filtered then "differentially Summed" via an Opamp.
Thanks for the valuable input John...Now, how close I am?
Attached Files
File Type: pdf SAA7350 RTZ sch.pdf (38.2 KB, 52 views)
__________________
Non é mai abbastanza...
  Reply With Quote
Old 12th February 2010, 05:41 PM   #608
JohnW is offline JohnW  Hong Kong
diyAudio Member
 
JohnW's Avatar
 
Join Date: Jan 2004
Location: Discovery Bay, Prague, Paris...
Hi Aparatusonitus,

Close your getting the idea, but....

Firstly, the XSYS 2 is very heavily jittered by the internal clock tree of the 7350. In your current implantation (if it worked), the final pulse energy would be also modulated by the jitter on the output of XSYS2.

Other issues - I cannot see how it would work... I will forward you a Schematic in the next 24 hours...

John
__________________
Life shouldn't be taken too seriously as at the end of the day you will not come out of it alive anyway…
  Reply With Quote
Old 12th February 2010, 09:12 PM   #609
loris.p is offline loris.p  Italy
diyAudio Member
 
loris.p's Avatar
 
Join Date: Sep 2006
Location: Milano
Default DaCapo

24 hours of continuous working..... still no noise..... I cross my fingers but everything is ok
( isn't it that when the caps grow old they get sick untill they die of natural ( fixed) death? :-)
  Reply With Quote
Old 13th February 2010, 12:52 AM   #610
JohnW is offline JohnW  Hong Kong
diyAudio Member
 
JohnW's Avatar
 
Join Date: Jan 2004
Location: Discovery Bay, Prague, Paris...
Hi Loris,

Good News, however I suspect theres still an issue. Yes - Caps do age, however in this circuit application, Cap ageing would not result in White Noise....

Still snowing here....

John
__________________
Life shouldn't be taken too seriously as at the end of the day you will not come out of it alive anyway…
  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
John Curl - Parasound amp Issue Zero Cool Solid State 11 20th August 2008 08:41 PM
FS: Pink Triangle Da Capo (UK) minniedog Swap Meet 1 28th January 2008 01:21 PM
WTB:Pink Triangle Da Capo (non-functioning) Studley Swap Meet 2 28th January 2007 04:46 PM


New To Site? Need Help?

All times are GMT. The time now is 07:45 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