How much hiss from power amplifier is too much?

[Overdose]

Too much hiss, is that which is overtly evident and affects the enjoyment of your music. That is not to say that it is noise out of tolerance of the product causing it, merely an individuals perception.

Here is a link about system noise. Perhaps you need to invest in a quieter headphone amp (note, not neccessarily more expensive). It is also interesting to note that the impedance of the headphones can affect the apparent intensity of the noise. Lower impedance headphones will appear noisier with any given amp.

Here is the problem in effect on a Mac and one that I too experienced.

 

[albireo]

I've owned a Creek Evo for a long time and for a while used it with a pair of Epos M5i, which I assume are quite similar to yours. No hiss, unless I stuck my ear on the tweeters while no music was playing and in total absence of environmental noise (cars, traffic, tv on etc)