Headphone amps for iPhone?

[chicken_wang]

I want better sound off my Sennheiser 650's and Beats PRO's (which I bought from an unsatisfied person on kijiji). I read that getting a headphone amp is that way to go. Portable or not I'm looking for something under the $150 mark. I'm thinking of purchasing the Fiio E5 or E7 but I'm not really sure yet.

EDIT: Scratch that, I'm looking for something portable because I'll be walking around outside with my headphones most of the time.

 

[kornphlake]

I'd start with something like a CMOY amp, search ebay for some good deals on pre-assembled units.

 

[viivo]

Check out the For Sale forum at head-fi. I picked up a nice, cheap CMOY there a while back, not to mention there are higher-end portable options and the people there are very helpful and the prices fair.

Not trying to advertise, just the world of audio is loaded with scammers and it's nice to know about places you can trust.

 

[alfa147x]

Look here:
http://www.jdslabs.com/

Also ebay "ipod line out" you'll be able to find something for less than $10

 

[nataku00]

The Sennheiser HD650's are open headphones... Not only will you get ambient noise while walking around, but people will hear your music as well. You will also likely need a 1/4" to 1/8" adapter for your HD650's to plug into most portable amp options.