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?
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Where can I find some information about these spdif transformer circuits and operation theory?
ezkcdude said:
why, is it for RF bypassing? Maybe the capacitor in the picture is optional.
Now I found some theory:
http://www.scientificonversion.com/technical_paper_1.html
macgyver said:
The 0,01µF is NOT optional!
It blocks the DC current.
The transformer will shortcircut the output if that cap is removed.
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!)
See ECdesigns ultimate dac with 1541 (long thread!)
seoman said:
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.
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 ).
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?
jean-paul said:
Actually, it does do harm. It adds jitter. Better to have only the cap on the source output.
Steve N.
Empirical Audio
Manufacturer
phn said:
Both is a good idea. You get the galvanic isolation as well as a fast receiver.
Steve N.
Empirical Audio
audioengr said:
I was not aware that caps add jitter. However I said "just in case" as one can not assume every possible source to be DC free. Of course just one cap is the best solution but this can only be done with known sources.
It's like with cd, dvd players and amps. I see caps both in the outputs of the sources and also in the inputs of amps. Hence, always 2 caps in series of which one can be easily omitted.
jean-paul said:
Caps add jitter due to dispersion caused by the dielectrics and their absorption. Use low-loss, low DA caps for low jitter.
Steve N.
Sounds god to me,if it works,I´ve heard some say the transformer is there only for groundloops..
audioengr said:
You are suggesting eliminating the DC blocking cap altogether on the SPDIF input circuit?
ezkcdude said:
If there are transformers at both driver and receiver, the answer is yes. If only one, then you need a cap. You will still need a cap at the driver transformer input, but not the output.
Steve N.
Ryssen said:
It will work, but not sound as good. You need the galvanic isolation that a transformers provides. Transformers also contribute less to jitter than caps, assuming that you buy good ones.
Steve N.
Better Spdif
I added the DS8922 buffer in a CD304MK2 with a SVHS connector, and suggested by EC i didn't use a 74/14 after SAA7220, only the DS.
http://www.diyaudio.com/forums/showthread.php?postid=931340#post931340
Don't know how it sounds, have no dac (yet) But on a scope the signal looked good. The transformer of a ringcore EC made to put in dac looks better to me compared to the standard simple one used in the CDP. See the scope signals from such a simple transformer here:
http://home.hccnet.nl/r.r.meijer/het uitgangstrafootje.html
I added the DS8922 buffer in a CD304MK2 with a SVHS connector, and suggested by EC i didn't use a 74/14 after SAA7220, only the DS.
http://www.diyaudio.com/forums/showthread.php?postid=931340#post931340
Don't know how it sounds, have no dac (yet) But on a scope the signal looked good. The transformer of a ringcore EC made to put in dac looks better to me compared to the standard simple one used in the CDP. See the scope signals from such a simple transformer here:
http://home.hccnet.nl/r.r.meijer/het uitgangstrafootje.html
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