Hi:
Thanks for considering an AVA product!
The Transcendence 5 preamp does include a headphone section; however, the strength of the T5 is its function as a preamp. In comparing the T5 which is our entry model tube preamp with the Corda that is dedicated headphone only amp I would tend to think the dedicated headphone amp would be better.
Having said that, however, I think you would be very pleased with the Transcendence 7. In the T7 the headphone stage takes its input from the line out stage so you will get all of the great sound that is delivered to a power amp along with a dedicated super fast and dynamic headphone section. Using the Transcendence FetValve circuit where we use the best of a tube circuit with the best of Fet circuit you get an extremely nice sounding piece of equipment. While this preamp in the SL chassis (no tone controls) is a bit more money than a dedicated headphone amp you do have the ability to run a power amp along with phones.
Hope this helps -- good luck with your selection!
Larry Jenkins