I'm generally a fan of tube pre-amps and I tend to reside in the "simpler is better" camp. Here's a nice simple one within your budget. Oh, and it is a quality headphone amp too.....
http://cls.audiogon.com/cgi-bin/cls.pl?preatube&1171652444
Not affiliate with the seller and haven't heard the unit, but like the concept.....
Enjoy,
TIC
http://cls.audiogon.com/cgi-bin/cls.pl?preatube&1171652444
Not affiliate with the seller and haven't heard the unit, but like the concept.....
Enjoy,
TIC