Years ago, I ran across an electronics hobby book that, as one of its projects, suggested assembling a crystal radio but running the output to the line input of a hi-fi amplifier, instead of the typical high-z headphones. The phrase, “you might hear things you hadn’t heard before” appeared, describing the possible results of such an experiment. I took the vague wording to refer to the improved frequency response of this setup over the typical cheap “All American 5” table radio of the era or over that of the high impedance headphones typically used with crystal radios.
I’m glad that in this case, the broadcaster made a good faith effort to put a high quality signal on the air. Of course, “results may vary” has accurately described the quality of the fidelity of AM reception for many decades. For instance, I was given an early 70s vintage Panasonic AM/FM table radio that has a fairly wide bandwidth and fairly good sounding audio on AM. I have also run across a CBS “Masterwork” receiver of the same vintage that has about the same characteristics in its AM section. Neither of these are DX radios, but they are very well suited to listening to local stations.
I first heard about AMAX in 1992. It was either on a commercial that aired on WAUD or in _Radio-Electronics_ magazine. After seeing what the AMAX logo looked like, in the magazine article, I kept an eye out for it while visiting local retail outlets. Unfortunately, none of the late-model radios that I saw had the logo, and all the ones that I tried sounded as if they had the typical ~3kHz audio response. The only difference I noted around that time was that the new radios covered up to 1700 kHz, in preparation for the expanded band. It was not until 1994 that I was able to get my hands on an AMAX radio (a Sony SRF-42). I had to buy it via mail-order, as it was not available locally. My point behind this story was that for those discerning radio buyers who cared enough to seek out a radio designed to the AMAX standards, the experience was frustrating.