I need to manage several line level signals (physically, not in software), and need to know what to expect. I was expecting AC signals, but am not quite sure. Are line level audio signals AC or DC? What Vpp can I expect?

  • $\begingroup$ A DC audio signal: does that even make sense to you? $\endgroup$ – Marcus Müller Mar 20 '20 at 12:40
  • $\begingroup$ No, it makes sense that the signal endpoint is some type of vibrating membrane, and AC is perfect for that. But it was an EE who insisted it was DC. Regardless, I need to switch a stereo signal without clicking in the audio, and have looked at CD4066 and other components. The best candidate was SSM2402 which doesn't require any antithump bits, but SSM2402 looks outdated. Can you recommend any noisefree chips like alldatasheet.com/datasheet-pdf/pdf/49101/AD/SSM2404.html ? I remember you, you're the gnuradio wizard! $\endgroup$ – user2497 Mar 20 '20 at 13:49
  • $\begingroup$ so, we're really leaving the realm of signal processing here, and cross over in electronics design. Anyway, there's no such thing as "noiseless" circuits at non-zero temperatures ;) I'm not a wizard! We prefer the term warlock. $\endgroup$ – Marcus Müller Mar 20 '20 at 13:52
  • $\begingroup$ Turns out the 'EE' who misinformed me is now a clairvoyant, who works with dream interpretation at a rate of 120$/hour... $\endgroup$ – user2497 Mar 30 '20 at 10:39

Audio signals on line level outputs are AC signals with no DC bias, so they run positive and negative around the 0V level. Many devices support 2VRMS output for full scale signal, so that is about 5.66 Vpp.


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