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Old 29th June 2011, 04:42 AM   #91
Previously: Kuei Yang Wang
 
Join Date: Nov 2002
Hi,

Quote:
Originally Posted by gabdx View Post
Here is the schematic picture.
This has the usual "reclocker" system (U1/X1) that just does not work at all, I hope you have removed it. You can later re-use U1 as divider for DEM reclocking if you like.

The wrong reclocking sounds like static at low levels and can sound like distortion at high levels.

The SPDIF Input circuit with the Transformer shown basically barely works.

If the output circuit is as shown and really has AD797 I suspect they are oscillating. In fact, for me AD797's always oscillate... ;-) Also, you do need the nominal supply line voltges for the Op-Amp as the circuit as shown produces significant (3.6V) DC offset, with normal dropout voltages etc. the Op-Amp's must run at least on +/- 12V.

Try something tame like OPA604 for starters, to make sure everything works okay.

The values of the Filter are also wrong for using the SAA7220, the analogue stage must use a precisely defined frequency response which is determined by the revision of the Filter (e.g. the SAA7220A has a different SAA7220C).

Ciao T
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Old 29th June 2011, 05:10 AM   #92
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Join Date: Apr 2007
Quote:
Originally Posted by gabdx View Post
Here is the schematic picture.
Hello

There is another little detail, normally there is a 1K ohm .047 uf filter to be connect to pin 20 of the CS8412, but in your schematic they connected it to pin 19, so it it should be connect to pin 20 like in the image I include.

Bye

Gaetan
Attached Images
File Type: gif CS8412 filter.gif (2.7 KB, 714 views)

Last edited by gaetan8888; 29th June 2011 at 05:15 AM.
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Old 1st July 2011, 03:27 AM   #93
gabdx is offline gabdx  Canada
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Quote:
Originally Posted by ThorstenL View Post
Hi,

The wrong reclocking sounds like static at low levels and can sound like distortion at high levels.

The SPDIF Input circuit with the Transformer shown basically barely works.

Ciao T
Hi Thorsten. At low volume there isn't any static, but not much instrument separation. It's only when the music gets very charged that I hear scratching noise + clipping.

Thanks Gaetan for noticing this, I will correct that, as for the DEM relocking, Spdif and disconnecting the clock and SAA740 I am lost.
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Old 1st July 2011, 06:47 AM   #94
Previously: Kuei Yang Wang
 
Join Date: Nov 2002
Hi,

Quote:
Originally Posted by gabdx View Post
Hi Thorsten. At low volume there isn't any static, but not much instrument separation. It's only when the music gets very charged that I hear scratching noise + clipping.
Do you have a PC with SPDIF output or a CD-Player and some test CD's, plus a 'scope (nothing fancy, 20MHz analogue 'scope should do, 60MHz or 100MHz is a Bonus)? I think you take some readings.

Quote:
Originally Posted by gabdx View Post
Thanks Gaetan for noticing this, I will correct that, as for the DEM relocking, Spdif and disconnecting the clock and SAA740 I am lost.
Best look at a generic Dac with CS8412 or CS8414 and I2S connection to the DAC (you can also look at the CS8412 datasheet, if you can work things out from there) and then remove the clock and the divider (4040).

For SPDIF, look at the CS8412/8414 Datasheet and use the simplest configuration given, remove the transformer (at least untill you have the tools and knowledge to correctly implement it).

For DEM Reclocking, there is plenty of information on this board.

Ciao T
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Old 1st July 2011, 09:17 AM   #95
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Join Date: Jun 2008
Thorsten Hi

With the excellent help of another member I have clocked the SAA7310, 7220 and TDA 1541A ( pins 2 and 4 )
Can I still apply DEM ( pins 16/17 ) leaving the above arrangement in place ?

Apologies if this is the wrong thread to ask this q

On decoupling, I have change the .22uf caps of my Arcam to .33uf and .47 and 1uf on MSB. This changed the sound quite noticeably - I liked it
I also notice some have reported gains using 2.2uf on the last MSB positions.
Do you agree with this value here

Andrew
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Old 1st July 2011, 09:21 AM   #96
Previously: Kuei Yang Wang
 
Join Date: Nov 2002
Hi,

Quote:
Originally Posted by AndrewGM View Post
With the excellent help of another member I have clocked the SAA7310, 7220 and TDA 1541A ( pins 2 and 4 )
Can I still apply DEM ( pins 16/17 ) leaving the above arrangement in place ?
Probably. You just need the correct frequency for the DEM Reclocking derived from the BCK.

Quote:
Originally Posted by AndrewGM View Post
On decoupling, I have change the .22uf caps of my Arcam to .33uf and .47 and 1uf on MSB. This changed the sound quite noticeably - I liked it
I use 4.7uF Wima MKS (Mylar) on the two MSB's, 1uF Wima MKP's (Polyproplylene) inbetween and Wima 0.47uF MKC's (Polycarbonate) for the LSB's, they where in my junkbox and fitted the PCB...

I like it well.

Ciao T
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Old 1st July 2011, 09:27 AM   #97
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Join Date: Jun 2008
Love it !

So, just experiment until you reach a point where you find the sound you like ?
Now that's like fun - no science, no calculations just get stuck in and do it.

That's just what a ' non tech ' person wants to hear

Andrew
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Old 1st July 2011, 09:33 AM   #98
Previously: Kuei Yang Wang
 
Join Date: Nov 2002
Andrew,

Quote:
Originally Posted by AndrewGM View Post
So, just experiment until you reach a point where you find the sound you like ?

Now that's like fun - no science, no calculations just get stuck in and do it.

That's just what a ' non tech ' person wants to hear
Well, I do think small, very low ESL Capacitors are better (they seem to do better), but the PCB layout of the Unit I have precluded using these and the Os-Con's on the MSB's that I would have preferred.

So I used a fairly slow DEM clock and whopping big capacitors on the principle that they this way they can do best what they do.

I guess it is the opposite of non-technical, it is looking at the layout and adapting your solution to the layout at hand and the contents of the junkbox, using experience as guide.

Ciao T
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Old 1st July 2011, 08:45 PM   #99
gabdx is offline gabdx  Canada
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Join Date: Jan 2008
To remove the relocking and put the dac in 2x OS, so far this is the recipe : remove Saa7220, link 2-16;3-15;1-18. Lift pin 23 on CS8412 and link it to ground.

I don't know if this will fix the noise issues.

For digital noise I use a 470pf capacitor in // at the output of the passive filter with around 47 ohm output impedance.
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Old 1st July 2011, 11:15 PM   #100
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Join Date: Jun 2008
Thorsten thanks for the reply.
I'll be changing caps then....have many spares and will apply the logic of the junk box !

On DEM topic, I lifted the BCK resistor on the dac board to feed in 11.2 and 5.6 to pins 2 and 4 straight from the new clock.
Clock will also let me have 2.8 that I can send to 16 for DEM - useful.
You can see it in the pic attached - ( this was before the caps changes I made ) but you can see pins 2 and 4 with clock feeds and the CK resistor lifted.

Pic 2 - is this another DEM option using WS.
Can I feed 2.8 mhz to pin 16 this way then remove the 470pf styrene cap that connects 16 to 17 and then gnd 17 ?

It's so confusing - well for me anyway - maybe all the experts out there find this sort of stuff easy but tbh I'm scared to wreck all the reasonable work I've done so far.
CD Player sounds much better than original = reasonable work !!

Andrew
Attached Images
File Type: jpg PICT0314.JPG (315.2 KB, 667 views)
File Type: gif dem-from ws_clock GORAN.gif (29.5 KB, 647 views)
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