Input Impedance Measurement


The only technical data for my NAD 2600 amps lists their input impedance as "more than 20K ohms." NAD did not know more. I need a more exact number for setting up my crossover. Can this be measured by an amateur? If so, what's the procedure? Thanks!
jdhames
952 ohms for your parallel network above; a 5% error. May or may not be significant for the particular application.
Bob your answer is correct but putting a 10K resistor in series with the input and feeding it with a 1V 1KHz sine will allow you to use simple ohms law. Measuring the voltage drop across the 10K to calculate the current flow, then subtract the voltage dropped across the 10K from the 1 volt input. Use R=V/I to calculate your input impedance, providing it is purely resistive. Good job Bob, I liked your answer too.
Hi Li thanks for the compliment; I could have suggested that method, which is similar to the way I sometimes measure speaker impedance curves. I just didn't want to attempt teaching ohm's law on-thread. Your approach is certainly valid & in fact a quicker avenue. Good work Mon!