i should ask before I botch SPDIF out..

[cuibono]

I am interested in improving my spdif output on my M-Audio Delta 1010LT. The output device is a CS8427, and currently uses cheap phono plugs.

I was planning on using this circuit

http://www.diyaudio.com/forums/attachment.php?s=&postid=764002&stamp=1131660111

from this thread:

http://www.diyaudio.com/forums/showthread.php?s=&threadid=67247&highlight=

I have built a pretty little board, and was getting ready to slice into my Delta 1010 when I read the data sheet a little more closely - specifically page 49 -

http://www.cirrus.com/en/pubs/proDatasheet/CS8427_F3.pdf

I realize the first circuit is not an automatic replacement for the circuit already around the CS8427 - in fact the Delta 1010 has the recommended ouput resistors (374 and 90.9) necessary to get 'consumer' SPDIF output (unbalanced, output impedance of 75 ohms, .5Vpp).

If I've got it correct, there isn't much I can do besides add a proper BNC connector, using proper 75ohm cable, and possibly change the output transform to a PE65612 from a possibly low-quality 'M-Tek D4101' (assuming the DC resistance of the winding is the same, which it looks to be from the schematic and measurements).

Can anyone point out anything I'm missing/got wrong/could improve?

Thanks much!

 

[cuibono]

I guess I could note that the input impedance of my DAC is 75ohm.

Is there any reason to adapt either of the voltage dividers before or after the transformer in the custom circuit (the Katapum circuit) to my chip?