If you can find a disc with a frequency sweep using a square wave on it, put this on repeat and let it play. Just make sure that you don't have any volume on the system as this can easily take out tweeters and / or sensitive mids.
As far as whether or not the preamp has to be on, that has to do with the preamp. Some preamps disconnect all the inputs via a relay when turned off. Some preamps even shunt unused inputs when turned on. The best way to do it would be to leave your preamp on, set the input selector to your cd player and then leave the volume all the way down and / or engage the muting circuit if you have one. This gives the cd player & interconnects a completed circuit path for the most voltage & current flow. Since square waves are much higher in average amplitude than a sine wave or most types of music, this will tend to break things in both faster and more thoroughly. Sean
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As far as whether or not the preamp has to be on, that has to do with the preamp. Some preamps disconnect all the inputs via a relay when turned off. Some preamps even shunt unused inputs when turned on. The best way to do it would be to leave your preamp on, set the input selector to your cd player and then leave the volume all the way down and / or engage the muting circuit if you have one. This gives the cd player & interconnects a completed circuit path for the most voltage & current flow. Since square waves are much higher in average amplitude than a sine wave or most types of music, this will tend to break things in both faster and more thoroughly. Sean
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