I'd like to work with this chip : http://www.cirrus.com/cn/pubs/proDatasheet/WM8804_v4.5.pdf

The S/PDIF Input mentioned in the datasheet states that the input impedance is 75Ohm. So I think that it should be used with 75Ohm coaxial cable, with RCA jacks.

So, my question is simple (and probably stupid too) : does any RCA connector work for S/PDIF interface ?

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    \$\begingroup\$ Yes it does, many audio devices have a COAX SPDIF input or output. If you connect these with a (75 ohm) COAX cable that usually just works. SPDIF does not use such a high frequency (a few MHz I think) so it is not so critical with regard to the connector. \$\endgroup\$ May 12, 2016 at 14:54
  • \$\begingroup\$ @FakeMoustache - it is subject to gross transmission line effects, but indeed not to connectors in the way microwave RF would be. Years ago I ran into an S/PDIF receiver implementation that I could reliably make fail or work by removing or replacing the terminating resistor in the receive circuit, though if I recall a later improvement to the DSP vendor's closely held firmware made their clock recovery more robust against waveform distortions. \$\endgroup\$ May 12, 2016 at 15:10

1 Answer 1


Yes, it will work with ANY RCA ("Cinch" in EU) connector. RCA connectors have a fixed mechanical dimension and it is not possible to make them 75-ohm (or 50 ohm or whatever). However using 75 ohm cable is desirable if you are using lengths ~>1m


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