Audigy 2 bay SB0290 repurpose

[taka]

Since I got the RTX 3070 my Audigy 5/RX headphone output received the coil whine from the video card. I tried multiple solutions with external power supply for audio card but none removed 100% the noise received from video card. So after many tries i considered repurposing the old Audigy external bay and since the new motherboard didnt have any PCI slots or drivers for SB0320 don't work with windows 11...

Target for today:

After opening the box and powering up the board all essential components work without I2S bus to the PCI card.

What i needed to use it's only 3 chips.
SPDIF to I2S - CS84154A
I2S to Analog DAC - CS4392kz
OP-AMP - 4556a
And a jumper wire from TOSLINK RX diode to SPDIF input

The unit it's powered from 12V line and I wanted to use USB for easy disconnect. So i had to use an step-up convertor.

Now after some soldering and tetsing. The Yellow wire is the SPDIF jumper. And the cable poweing the device it's just an old mouse cable.

No more coil whine induced into the headphones because the Audio source and the DAC-OP Amp are connected with Fiber cable.

Hope this helps someone to give some life back into his SB0290!

Cheers!

Simplified schematic for the above.

 

[Conelect]

Hello @taka,

Great work on your project.
I have one of these units that stopped working. I am not getting any oscillator function on U4 between C43 and C41,
This being the main micro controller I am thinking that maybe it died.
Are you able to check your unit with a scope to see if there is any oscillator on your unit while it's not connected to the Audigi card?

Cheers
Pete

 

[taka]

Hello @taka,

Great work on your project.
I have one of these units that stopped working. I am not getting any oscillator function on U4 between C43 and C41,
This being the main micro controller I am thinking that maybe it died.
Are you able to check your unit with a scope to see if there is any oscillator on your unit while it's not connected to the Audigi card?

Cheers
Pete

Hello,
U4 is the Firewire transceiver and should work with only 12v from the Firewire cable. I dont have the option to use a scope right now but the signal should be there.

Datasheet for that chip HERE!

This one has a 3.3v power, also chek the downstep

Cheers,
Taka

BTW the main logic ( 2microcontrolers ) is here for the volume and input output selection.

Datasheet HERE!

 

[Conelect]

Hey thanks a lot for the extra info. You shouldn't have gone to all that trouble. I appreciate your effort.
Yes you are right about the transceiver. I must have looked up the wrong part number and mistaken it for a TI micro. I will try and hook the box up to the firewire port to see if it starts the oscillator. The two other Philips micros have a clear oscillator signal present.
Maybe I will try reinstalling the software again. It could be a driver issue. I can't understand why the box just stopped working. The sound card diagnostics come up clean but I don't think they cover the interface box. I noticed the 5V regulator on my unit is dissipating a lot of heat. If I get my unit working I am going to try and see what the minimum functional input voltage is. I will let you know how that goes.

Thanks for your help.
Cheers
Pete