I use a sangean RCR10, which is stereo, but I can dump it to mono in the DAW. They make really good radios. The one I have is sort of a good average system - simple bass + treble controls + a bass boost feature so I can switch between how people might be using a system like that - switching between "consumer flat" and "consumer hyped"

I have an old bose wave radio as well but they do so much processing to get the "bose sound" that it's unreliable for testing.