I had the same problem. Muting the microphone (&other input sound devices) did stop my PC hissing.
The problem is that KMix options are quite confusing for me: what does Microphone and Microphone amplifier have in common with sound output? -- Hiss on sound card https://bugs.launchpad.net/bugs/139848 You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
