I am not sure why you are looking at the input impedance on your Z5450 when you are looking to drive(output) to your headphones, 2 different things.

I will guess the Z5450 headphone jack is a very low line level voltage(0-3V) out for headphones and not passed through it's amp at all. So yes, you could use a headphone amp.

Last edited by jakewash; 03/25/10 06:46 PM.
Jason
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