[feigeibomber]

Hello! I'm sure this has been asked numerous times before, and that you may be thinking, why is he posting this, he should just search the forums!! The truth is, I've tried sweeping the web and I have still yet to find an answer, however, I did learn about output impedance, but i'm still quite confused as to what input impedance is, any help?
Thank you!

 

[stv014]

It is the impedance of the line inputs of the amplifier, and the load your DAC or other source needs to drive; a typical value is around 10 kΩ. Usually, it is not important, but if it is very low (or multiple amplifier inputs are connected in parallel with a splitter), then some sources may have difficulty driving it. Also, some amplifiers, when turned off, will have lower and non-linear input impedance, causing distortion in a setup where there is another parallel amplifier using a splitter.

 

[PleasantSounds]

You can think of input impedance as an indicator of how much current is needed to drive the device: the lower the impedance, the more current is needed.
 
Output impedance on the other hand, can be treated as indicator of ability to deliver current.
 
So with amps typically you would want high input impedance and low output impedance, but the latter may not be as critical if you have high impedance headphones: they still need similar amount of power for the same level of volume, but it is achieved through raising voltage levels much higher rather than through the ability do deliver more current.