The 75A4 is not a very good receiver for AM when left stock, as many owners do who have an eye toward maximum collector value unmodified. The high distortion and poor response of the audio stages, and the inadequate passband with stock mechanical filters, make this an unpleasant receiver for most AM reception. Aesthetically, the receiver is somewhat the orphan, mismatched in size against the senior Collins AM tabletop transmitter, the 32V series, yet not really a good optical fit with the junior Collins tabletop transmitters that were not capable of AM. Although marketed alongside the KWS-1, this transmitter itself falls short on AM, with only one sideband and a carrier, and an unsavory number of compromises against audio quality. But, as you already have seen with the posts about modification and re-working, the 75A4 can be made to sound good on AM. If you buy into one at below market prices, the idea of modification is easier to consider. Or, you can procure the older 75A series that were oriented toward quality AM. By the time the A4 came along, Collins had begun to shortchange AM in favor of other, incomplete voice modes.