John Swenson wrote in the "Upgrading the clocks in the SBT - is it necessary?" thread.
"For example the impedance of the output is just as important as the jitter of the signal, the official spec says outputs and inputs should be 75 ohms, but in reality the impedance of outputs, inputs and cables varies all over the place from 25 ohms to 120 or so. What matters is that they match as closely as possible. So if your DAC has an input of 90 ohms, it doesn't matter if the source has precisely 75 ohms, you will get better results if the source is closer to 90. I have actually seen a case where a reclocker sounded better, even though the jitter on the output was worse than on the input, BUT the output impedance more closely matched that of the input on the DAC." This raises several questions not really specific to Squeezeboxen, but hey, thats where we all are. 1. When reading technical reviews of various digital sources, how come no one measures the actual output impedance? Its always "assumed" to be 75 ohms. 2. How difficult is it to measure this spec? 3. Will the actual output impedance vary from unit to unit, or will it be the same for a given circuit? 4. Is it difficult to measure the actual impedance of a digital cable (including the plugs, RCA, BNC, etc)? 5. When reading technical reviews of various DACs, how come no one measures the actual input impedance? 6. Would it be possible to construct a device to insert between sources and DACs for optimum results? Ideally this would have a facility to monitor and adjust impedance for an ideal match. ------------------------------------------------------------------------ konut's Profile: http://forums.slimdevices.com/member.php?userid=1596 View this thread: http://forums.slimdevices.com/showthread.php?t=95614 _______________________________________________ audiophiles mailing list [email protected] http://lists.slimdevices.com/mailman/listinfo/audiophiles
