Take a listen to the AM Stereo airchecks on this site:

http://www.1240keva.com/airchecks/

KEVA is an 880-watt Class C station in Evanston, Wyoming, using a
vintage McMartin vacuum tube (valve) transmitter and a complete
1983-era audio chain: a CRL AM Stereo Preparation Processor, a CRL AM
Stereo Maxtrix Processor, and a Motorola C-Quam AM Stereo Exciter.

The audio in the MP3 clips was recorded from KEVA's Motorola AM Stereo
Modulation Monitor, so you are hearing KEVA exactly as they sound on
the air -- not from a direct feed from their audio board.

Now, for those of you who have heard IBOC or DRM... can digital AM
ever sound this good? I don't think so... there's only so much
quality you can squeeze out of a 20 to 36 kbps data stream. At this
point, neither IBOC nor DRM have managed to eliminate the swishy,
gritty, phasey, heavily artifacted "28.8K RealAudio Web-Cast" type of
sound from their digital audio. And except for a MAJOR revolution in
the science of "lossy" audio compression, I don't think they ever
will.

Digital does have its advantages... but not in AM audio quality!