Spdif transformer

[macgyver]

What you think about this kind of circuit, is it ok?



Where can I find some information about these spdif transformer circuits and operation theory?

[ezkcdude]

Add a bypass cap on the ground input.

[macgyver]

Originally posted by ezkcdude
Add a bypass cap on the ground input.

why, is it for RF bypassing? Maybe the capacitor in the picture is optional.

Now I found some theory:

http://www.scientificonversion.com/t...l_paper_1.html

[seoman]

Originally posted by macgyver


why, is it for RF bypassing? Maybe the capacitor in the picture is optional.

Now I found some theory:

http://www.scientificonversion.com/t...l_paper_1.html

The 0,01µF is NOT optional!
It blocks the DC current.
The transformer will shortcircut the output if that cap is removed.

[tubee]

A DS8922 buffer circuit would be better imo. Build a receiver circuit in dac too. I removed the spdif transformer in the cdp.
See ECdesigns ultimate dac with 1541 (long thread!)

[macgyver]

Originally posted by seoman


The 0,01µF is NOT optional!
It blocks the DC current.
The transformer will shortcircut the output if that cap is removed.

Yes it blocks the DC and it prevents the transformer to go saturation. They didn't use it in AES1998 paper (page 34) so that's why I was curios.

[jean-paul]

If there is a cap/transformer in the output of the feeding device this particular cap can be omitted but it won't harm to leave it there ( just in case ).

[Ryssen]

A DS8922 buffer circuit would be better imo. Build a receiver circuit in dac too. I removed the spdif transformer in the cdp.

You mean a buffer instead of transformer,or just remove the transformer?

[phn]

Why is a chip buffer better than a trafo in this case? Everywhere else a trafo seems to be the superior alternative. Why not use both?

[audioengr]

Originally posted by jean-paul
If there is a cap/transformer in the output of the feeding device this particular cap can be omitted but it won't harm to leave it there ( just in case ).

Actually, it does do harm. It adds jitter. Better to have only the cap on the source output.

Steve N.
Empirical Audio
Manufacturer