The best amp I have for low impedance cans is my Head-Direct EF1, but it is also the most expensive one I have, by far. The old Octavart does a nice job powering easy to drive Grados and Ultrasones. I do not know how it sounds with the Denon headphones you own, but it will definitely makes the Grados sound awfully nice.
EDIT: Skylab made a really good review of it here: http://www.head-fi.org/forums/f5/rev...ne-amp-361841/
Link to mine: techPowerUp :: Head-Direct EF1 Hybrid Headphone Amp Review :: Page 1 / 5








). No offense.
