Originally Posted by arnold006287
Okay well now I did a bit more research and learned more about what I need...But now I guess I have a new question; for a headphone that with a relatively low impedance (16 ohms) and a sensitivity of 97db/mw @ 1kHz be okay with an amp at an impedance of 32 ohms? And if not, is there a way you can cut down the impedance of an amp...and I guess out of all of this, the last question would be...am I going to notice a difference if I amped these headphones?
First, USB is a different connector because it transmits different kinds of information. A 3.5mm jack in our culture - if used as an input - transmits 2-channel analog signals to provide a stereo music signal. A USB connector - if used as an input from a PC - is used to transmit both power (5VDC) and a digital signal. That digital signal can be anything - programs, data files, a digital music signal, etc. - but you need hardware/software on the other side to know what to do with it. IOW, the two connectors have nothing to do with each other.
Second, as for your second question above - there's not enough information to answer it. You haven't even told us what headphones you're talking about. 32 ohms output impedance sounds like a tube amp. That's not going to result in a very high damping factor, but depending on the headphone, it may or may not be OK. It really depends on the inherent damping factor of the headphone and since those are not measurements that are ever published for headphones, you would have to rely on other peoples' reports on the traits of those headphones. For instance, I have tube hybrids and tube amps that may have output impedances of 10 to 32 ohms and they may handle a 16 ohm pair of IEMs just fine. For most very efficient IEM's, it depends more on the quietness of the amp not its output impedance.
I would suggest that you ask the same question - being specific as to headphones and amp - in the headphone section of Head-Fi. There are more questions than one can count that begin with "Is Headphone X better with or without an amp?" They all seem to get answered, though.