Hi Bill,
In the analog domain 52 ohms vs. 75 ohms is, as you appear to be saying, an insignificant difference. However when it comes to digital signals, the effects which come into play at the very high frequencies which are present to a significant degree in their risetimes and falltimes (those terms referring to the transition times of a digital signal between its two voltage states, which in the case of digital audio signals involve significant frequency components extending to tens and perhaps hundreds of MHz) 52 ohms vs. 75 ohms is a considerable mismatch. The reason being that at those frequencies "RF transmission line effects" come into play. Which result, in the case of a significant impedance mismatch, in signal reflections bouncing back and forth between the connected components, causing some degree of distortion of the waveform as received by the destination component.
Whether that waveform distortion will result in sound that is subjectively better, worse, or the same than if the impedance mismatch did not exist will depend on a great many complex and essentially unpredictable variables involving the technical characteristics of the signal, the cable, the length of the cable, both of the connected components, and (from a subjective standpoint, at least) the rest of the system.
My point is simply that such a mismatch can be expected to cause the sonic performance of the cable to be inconsistent and not very predictable among different systems, and very conceivably also among different cable lengths.
In any event, enjoy! Best regards,
-- Al
In the analog domain 52 ohms vs. 75 ohms is, as you appear to be saying, an insignificant difference. However when it comes to digital signals, the effects which come into play at the very high frequencies which are present to a significant degree in their risetimes and falltimes (those terms referring to the transition times of a digital signal between its two voltage states, which in the case of digital audio signals involve significant frequency components extending to tens and perhaps hundreds of MHz) 52 ohms vs. 75 ohms is a considerable mismatch. The reason being that at those frequencies "RF transmission line effects" come into play. Which result, in the case of a significant impedance mismatch, in signal reflections bouncing back and forth between the connected components, causing some degree of distortion of the waveform as received by the destination component.
Whether that waveform distortion will result in sound that is subjectively better, worse, or the same than if the impedance mismatch did not exist will depend on a great many complex and essentially unpredictable variables involving the technical characteristics of the signal, the cable, the length of the cable, both of the connected components, and (from a subjective standpoint, at least) the rest of the system.
My point is simply that such a mismatch can be expected to cause the sonic performance of the cable to be inconsistent and not very predictable among different systems, and very conceivably also among different cable lengths.
In any event, enjoy! Best regards,
-- Al