Headphones affecting how amps sound? You bet they do!

Transducers are reactive loads

Adding a reactive load to a circuit changes the characteristics of the circuit

Naturally, it will change the output signal, and hence how it sounds.

Ok, so this is a "duh" thing to some of you. But ever tried listening to the difference?

Here is the output from the headphone-out of a US-144, fed to the line-in of ALC888 -

http://www.mediafire.com/?3slz1b2ohj2c29f

And here is the same output with a MS-1 in parallel -

http://www.mediafire.com/?kpzxaqyp567vuqe

To the headphone, the line-in with high-impedance does not affect the sound, like how an oscilloscope should not affect whatever it is scoping.

But to the line-in, the sound has changed.

The 'normalized' suffix in the filenames - voltage across line-in is lowered with the low-impedance headphone load in parallel, hence files are normalized to prevent the 'loud effect' from affecting perception.

The amp wants to put out an accurate signal. But by the time it reaches the headphone the headphone sees a different signal instead.

Needless to say, different amps and headphones affect each other differently.

So system-matching between headphone and amp? Yes! And it goes further than just how the sound signature of one compliments the other.

Here's the same test done on iM716 in both 'Bass' and 'HD' settings.

http://www.mediafire.com/?x35il5dcd7z2v