I thought EMI was Electromagnetic interference, which comes from all electronic devices. It was my iPod Classic. Tested it as well with my iPod Video. Same thing happened. I was testing the latest components that start shipping this month from JDS Labs. Apparently they changed a few things inside. Anyways, I couldn't find the time to do the review so I sent it back, unfortunately.
EDIT: Please keep in mind I'm using some pretty sensitive CIEM's....
EMI from iPod? I don't realize iPod is capable of radio wave emission (of significant level) at all. Are you sure it isn't the noise from some other components? For example, microdrive from older iPod, etc. I could understand if it is an iPhone cause those are known to be real bad with EMI (I am using a Samsung for testing, btw). Also, what headphone you were using at the time? I tested with SE530, which is notorious for picking up hiss. But I am certain there are worst out there. Even so, wait till you hear the FSM-01 before you know what counts as really bad hissing - it is like having two mosquitos flying inside your ears.
My C421 are all current models btw.
Edited by kenman345 - 8/1/12 at 8:41pm