I haven't used "amixer" before, so I'm working on only a few minutes worth of experience. However, I think that your sound card may use different names than "Mic Input" and "Output Mixer Line Bypass". The command:

amixer scontrols
shows a complete list of what the man page calls "simple mixer controls". The command:

amixer scontents
shows the list of controls as well as their settings. On my system, I don't see "Mic Input" or "Output Mixer Line Bypass".

I'd still recommend sticking with "alsamixer", since it wraps stuff together into a GUI that is conceptually similar to what you'd see under MS Windows or X Windows (don't know how Macs do this).

I had to open my server's case to verify that I am using a Hauppauge WinTV-Radio card of very old vintage (purchased 2004). It's a PCI card, for one thing; for another, it receives only NTSC analog signals, so it's definitely no good any longer for receiving over-the-air TV signals here in the U.S.

Hauppauge's Web page shows some new PCI-E WinTV cards with FM tuners. You have to go to "TV tuners for system builders" to find them, though. I have no idea if these newer cards have support under Linux.

For my card, the package "fmtools" provides command-line support for turning the radio receiver off and on, tuning the frequency, and setting the radio volume, all with a single command called "fm". Pretty handy. I had a refresher course in setting it up because I just today migrated the card to a different system. All appears well, but tonight's recording will put it to the test.