Does anybody broadcast true hi-fi AM anymore? The FCC limits the total
bandwidth to 20 kHz or an audio bandwidth of 10 kHz but I think most
broadcasters don't even go that far. More than that, nearly all the
broadcasters now seem to be pre-emphisising the trebles, and AM usually
sounds shrill on a wide bandwidth radio. I assume they do this to somewhat
compensate for the normal IF roll off in a typical radio. Add in the other
audio processing that broadcasters use, and AM doesn't really sound a whole
lot better on a wide band radio.


snip

Getting wideband IF transformers will be a real problem. I don't know of
any NOS sources for them.


A bunch of approaches exist.

In the 50s and 60s, several RF suppliers-I get Miller and Millen
confused,one at least-offered sets of cans to build, essentially,
crystal radios that you hooked up to your hi-fi preamp. They still had
high-gain inputs without RIAA for 78s in those days, I presume. This
was considered the best possible way to demod AM. I don't know how
well it would work with the crapped-up bands and disinclination to run
long wire antennas and real RF grounds today.

Later on, Klipsch dealers would have a similar set built on a display
board hooked to a matching xfmr which they would hook to a K-horn.
With no power supply or amplifying devices, if you were within a few
miles of a 50-kw station-or if you were in a very quiet room with a
big longwire and really good ground, even at night or in the sticks-
you had a surprisingly loud and clear audio feed. I can very clearly
remember hearing Simon and Garfunkel's "The Sound of Silence" for the
first time on this arrangement. When did that come out? Late 60s I'm
guessing.

Before that even, people in the 30s' (or so they say...) would modify
old A****er Kents into tuners by removing the output section and
providing a B+ and filament supply and furnishing an amp and speaker.
Camera repair guru Ed Romney, who has since went to the big
transmitter shack, talks of this in his radio repair book. He may have
even reprinted the article: I know I had ordered one on interlibrary
loan back in the 80s. Consumer Reports recommended this as an
alternative to the E.H. Scotts and Philharmonics of the day.

Finally, unless you really like heterodyne whistles, you will want a
10 kHz notch filter, or a rolloff.