Soekris' DAC implementations

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Tyimo

Member
Joined 2002
Auto_____________N-C_______N-C
I2S______________GND______GND
SPDIF1 (Coax)_____N-C_______GND_____(Sensitive LVDS receiver)
SPDIF2 (Toslink)___GND_______N-C______(Standard 3.3V digital level)

If you don't connect anything to the input select pins it will search the three inputs for a valid signal and lock when found.
Click to expand...

What are this: SPDIF1 (Coax)_____N-C_______GND_____(Sensitive LVDS receiver)??? Are these pins?
 
iTiberius

iTiberius

Member
Joined 2005
Tyimo said:
What are this: SPDIF1 (Coax)_____N-C_______GND_____(Sensitive LVDS receiver)??? Are these pins?
Click to expand...

Tyimo,

This is what I understand from above Soekris post.
There are two pins who make hardware input selection.
To select S/PDIF 1, which is for coaxial, you need to ground INP SLCT1. Leave INP SLCT0 not connected.

If you are using a commercial s/pdif output source, than your product should have already an s/pdif transformer, this should provide required isolation. You may connect to Soekris DAC directly using SPDIF1 IN+/-. How to connect these do not make much sense as long your source have a isolation transformer.

Regards,
Tibi
 
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T

Tyimo

Member
Joined 2002
If you are using a commercial DAC, than your product should have already an s/pdif transformer, this should provide required isolation. You may connect to Soekris DAC directly using SPDIF1 IN+/-. How to connect these do not make much sense as long your DAC have a isolation transformer.
Click to expand...
Yes, that would be super!!!! I use a commercial USB to Spdif converter.
So the question is: use SPDIF1 IN+/- or SPDIF1 IN+ and GND with my coax cable?
 
TNT

TNT

Member
Joined 2003
Paid Member
Tyimo said:
O.K. understand. BTW there is only shown "pwr in" and no +DC or -DC......
Click to expand...

The two outer pins are "hot" and both the two middle pins are ground.

Connect + to one of the outer pins and - to the other outer pin. It doesn't matter which (yes - its OK!)
Connect the ground of your power to one of the two middle pins.

You are good to go!

//

PS This works because you are feeding DC to a full rectifier bridge which sorts out the polarity for you.
 
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RollE2k

Member
Joined 2007
Can anybody who have the dac try with both direct 7.5VAC and regulated dc (perferably by good super reg or shunt) and tell if there is any big difference?
Either i'm going to order custom R-cores at 7.5V or else i'll run it with Salas shunts, But it would be good to have some references if it's worth it before i decide.

I already have my nice made compact dual-salas shunts boards, with common mode choke and everything - so it's either custom r-core, or order parts for these boards!

I recieved my DAC board today also :)
 
E

Eldam

Banned
Joined 2012
RollE2k said:
Can anybody who have the dac try with both direct 7.5VAC and regulated dc (perferably by good super reg or shunt) and tell if there is any big difference?
Either i'm going to order custom R-cores at 7.5V or else i'll run it with Salas shunts, But it would be good to have some references if it's worth it before i decide.

I already have my nice made compact dual-salas shunts boards, with common mode choke and everything - so it's either custom r-core, or order parts for these boards!

I recieved my DAC board today also :)
Click to expand...

Is there any interrest to have a low flat (& wide bandwidth) impedance with such a DAC using a shunt reg?

How does the embeded diodebridge influence a DC Power Supply ? Just half of the half bridge has an action : - 0.7V (TNT member answered me about that on the official vendor thread about this question) ? (I believed even with DC you will have the drop of the entire half brifge : so 1.4V with 2 diodes ! I never thinked about feeding a diode bridge with DC already :) )
As the noise rejection with the embeded LDO seems to suffice, I just made myself a simple linear Pi DC :

R-CORE 9V/30VA -> Shotky diodes (2 bridges with a common zero ref/Gnd) 2200 uf --> 220R -> 2200 uF ! So with the +/- : 4 caps, 2 resistors (no Pi resistors on the two common zero/Gnd rails). I plan as well to add 4 resistors 10R in serie between each output diode bridge and the first cap which manage the pulsed current ... does a RC 10R/2200 uF is a good targett ?) !

Give me a final 10.7 DC before the embeded bridge so the 10 V minimum DC advised ! (10 to 12 DC advised if no AC feeding with a standalone traffo 7V-8V choosed !)
 
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