11-26-2013, 07:57 PM
While an AM transmitter is an effective way to listen to a CD player or other source on a vintage radio, there is still a significant loss of fidelity. Keep in mind that the IF transformer selectivity curve effectively cuts the higher audio frequency sidebands and limits high freq response to less than 5 KHz (Unless you have one of the wideband "high fidelity" models!)
With a direct connection, frequency response of the audio circuitry extends to 10 KHz or more and there is a definite improvement in quality when you don't modulate and then demodulate the audio signal.
Having listened to the same audio signal from a CD direct into the audio stage and also AM modulated, there is no comparison in quality. This is why I suggested keeping the audio input so you can appreciate how well these radios audio sections can perform independent of the limitations of AM technology.
With a direct connection, frequency response of the audio circuitry extends to 10 KHz or more and there is a definite improvement in quality when you don't modulate and then demodulate the audio signal.
Having listened to the same audio signal from a CD direct into the audio stage and also AM modulated, there is no comparison in quality. This is why I suggested keeping the audio input so you can appreciate how well these radios audio sections can perform independent of the limitations of AM technology.
