Hello to all and thanks for the quick replies and ideas. A special thanks to Jack from Micca for jumping in as well. Jack - yes, I did get your email but I was on the road all weekend on a business trip.
Mochan - I don't use the Zen anymore because my daughter appropriated from me! That and I prefer to have only one device to carry around at work. Also, with using the cell phone as my source, I can listen to my music and not miss calls as the music stops when a call comes in.
So anyway, I just got home today and I've been trying to get some other headphones to work with this little amp. Unfortunately, I can't find my PX100's but I wasn't planning on using them anyway because the mp3 player on the phone pushes those fine with plenty of volume.
I did try the amp using my daughters full-size cans (non-NC) and it's the exact same thing. There is a tiny bit of amplification from phone to amp to cans - and I mean tiny. Only by directly A/Bing them can you even tell there is a difference.
As to there being a problem with the Bose QC15's NC phones and an input volume limiter, there is a two way switch inside but that is only for dampening down loud sources like airplane announcement circuits and the switch was set to high anyway. There is no limitation of allowed gain in the cans as I hooked them up to a larger amp and they drove the cans just fine.
I can only conclude from this that the gain that is achievable from the EiiO 7 is very small, and as such only really good for small headphones such as IEMs or other easy-to-push headphones. I was hoping to find an amp that could push larger headphones with more gain. Either this unit cannot, or it is defective. I'm still inclined to return them unless someone else has another idea. I admit that I am not by any means knowledgeable in this area. And I know how you all feel about Bose, but these QC15s are just great for what they do - noise cancel. And for someone like me who cannot tolerate IEMs for any length of time, they are the only choice.
If someone can recommend a small, dedicated headphone amplifier that can get it done (mp3 -> amp -> QC15s playing louder) then I am all ears, pun intended! At this stage of the game I'm thinking I will just have to find a better source with more gain. I was a little suspect of the whole dedicated headphone amp thing as it is because in the end it just adds another piece of gear to my portable set-up.
M