Originally Posted by onebigunion
What is the impedance of the headphones. Many electronic devices exhibit hiss with low impedance (less than roughly 32 ohms). I have no problem with Audeo PFE or Audio Technica AD900, I beleive both are 40 ohm. I doubt an exchange will solve the hiss issue, this exists even on many dedicated music players. Only solutions are different phones, different device, or put a resistor in series with your phones.
Thanks, this was the problem.