Next the AF amp. We could use this one Andy's already designed.
EDIT: Andy pointed out the need for a preamplifier if we use his but it would drive a speaker so is an option if you don't care for headphones. Andy's AF amp
OR We can throw this one in in Spice see how it works. Find and fix any problems and then build it. I posted the spice file for it a couple of post back.
I did a rather simple test and hooked the output of my AF generator to my headphone with my meter to monitor the signal. The test told me 20 mv rms is all I can stand on my headphone. The sim says I will have 212 mv rms 10 mv input so it should be plenty for headphone listening.