M-Audio SuperDac

[Cobra2]

Tried to reply to the http://www.diyaudio.com/forums/showthread.php?threadid=9616&highlight=superdac tread...but it did not work..?

I have tried some of the "usual" mods to this unit:
1: Tantal-cap 4.7uF
2: OsCon 47uF(had one...)
3: Tantal 10uF
4: DAC analog supply caps 56uF Elna
5: DC-block-caps: Bi-pol 47uF bypassed w. 470nF
6: Op-Amps OPA627 (Bal-out) AD825 (RCA)
7: Extra filter for DAC Analog supply
8: RCA-connectors
---------------------------------
To come: PSU-upgrade including caps....
---------------------------------
Have tested between every change. Steps 1-4 did only give small changes, 5 was a great leap, step 6 was ofcourse even better....
---------------------------------
Please tell me where to implement a separate CLOCK..?
---------------------------------
Arne K
Norway

 

[fmak]

To come: PSU-upgrade including caps....
---------------------------------
Have tested between every change. Steps 1-4 did only give small changes, 5 was a great leap, step 6 was ofcourse even better....
---------------------------------
Please tell me where to implement a separate CLOCK..?
---------------------------------
Arne K
Norway [/B][/QUOTE]
--------------------------------

Use a separate beefy transformer and this has a big improvement.

You should also improve the filter network with all those cheap ceramic and mf resistors.

 

[Cobra2]

New tweaks...:

Having read somewhere on the web-pages at TAG McLaren, they had a upgarde service for some product changing the AK4393 DAC-chip with AK4395, I decided to try the same!

Have also done a little re-routing of the error-detection on the CS8414.
And new analog filter-caps.

So far I'm pleased, but hardly worth the $$ (?).

Arne K

 

[Cobra2]

For the brave...

The DAC-chip;

Arne K

 

[Elso Kwak]

Clock

Hi Arne,
Is there a clock on board? I don't see a crystal.
Maybe the DAC and digital filter can run on a asynchronous (stand alone) clock.
You have to dig into the datsheets. Some Delta-Sigma DACs have this feature.

 

[peranders]

I'll guess that the reciever produces the clock signal. The AK4393 has internal digital filters which every(?) delta sigma DAC have.

 

[Cobra2]

No onboard clock...
BTW, have 8 x AK4395 for trade / sale...

Arne K

 

[Elso Kwak]

Clock Synchronization

Hi Arne,
Maybe this thread answers your questions:
http://db.audioasylum.com/cgi/m.pl?forum=tweaks&n=55618&highlight=elso+delta+sigma&session=

 

[Cobra2]

Some answers, some (new) questions...

And getting into I2S seems more and more interesting...
Maybe next tweak?

Arne K

 

[Pjotr]

Hi,

The AK4393 as well as the AK4395 can spit out 4V_pp into 600 ohms directly. Anyone considered removing all the op-amps and using passive 50 kHz low pass filters? No need for + and – 15V anymore then.

Cheers

 

[hottyson]

I have tried some of the "usual" mods to this unit:
1: Tantal-cap 4.7uF
2: OsCon 47uF(had one...)
3: Tantal 10uF
4: DAC analog supply caps 56uF Elna
5: DC-block-caps: Bi-pol 47uF bypassed w. 470nF
6: Op-Amps OPA627 (Bal-out) AD825 (RCA)
7: Extra filter for DAC Analog supply
8: RCA-connectors
---------------------------------

Could one skip steps 1-5 and just add op-amps?

Wouldn't OPA627's work for the unbalaced too?

Thanks

 

[Cobra2]

Could one skip steps 1-5 and just add op-amps? Wouldn't OPA627's work for the unbalaced too?

Yes!
(Just remember the RCA-out first go thru' the "balanced" op-amps)

Arne K

 

[hottyson]

Yes!
(Just remember the RCA-out first go thru' the "balanced" op-amps)

Arne K

So does that mean that the AD825 a better choice for the RCA? What would happen if I use OPA627 in both? The reason I ask is that I have alot of OPA627 on hand at the moment. Are there other op-amps that you have tried that sound better for the RCA?

(Sorry, if these seems like silly questions but I am new to DIY.)

 

[Cobra2]

The OPA627 is very good (and expensive), and I just wanted to add some coloration to my preference, but you may use the OPA627 everywhere if you have them...
(Want to trade?)

Arne K