[mboxler]

I'm playing with an ESP32-WROVER development kit and SqueezeESP32 to stream music.  First was I2S into a PCM5102 DAC, now S/PDIF into the coaxial inputs of other DACs.  Not really knowing what I was doing, I connected ground and S/PDIF out from the chip pins directly to a male RCA jack, then into the DACs.  Sounded great, but was later told that I should have placed a 100nf capacitor and a voltage divider in the circuit to drop the voltage from 0 - 3.3 volts to -.5 +.5 volts (which I believe is the consumer S/PDIF specification).

Both a Schiit Bifrost and a MiniDSP locked into the "raw" signal.  Can someone explain to me why the filter is needed?

Thanks, Mike

[happyrabbit]

I bet the Bifrost and the Minidsp might rebuffer it to TTL levels.   I wouldn't lose sleep over it.   A Shielded Coax cable might be helpful.

Dwight

[Elizabeth]

web info"
"The output voltage level for SPDIF is 0.6 volts maximum, with input voltage levels of 0.2 volts. SPDIF signals may also be provided as TTL voltage levels"

[art]

The cap is there to remove the DC part of the signal.

[mboxler]

Thanks for the replies.  I understand what the filter does, just surprised that the DACs worked fine without it.

I got lazy and bought a used S/PDIF card designed for a PC motherboard with a S/PDIF header.  Ran +5 volts and ground from my power supply and the raw signal from the ESP32, and now have both toslink and coaxial outputs.
 


It's now in a wood box feeding the DAC ahead of my headphone amp.  A real cheap and cheerful squeezebox steamer.

Mike