Don't return them, try with a decent headphone amp first.
I'm on a hunt for a new pair of headphones for my axe and have been trying very many different headphones(closed back.open back, in ears, on ears... , different impedances, different brands, from 50-2000$ .
For some of the various headphones the headphone amp in the Axe Fx II is sufficient, for some of the headphones you only need to turn up the output knob to get good results. But for some headphones it sounds shrill and almost distorted and there is no umpf in the tone. It is like there is a lack of bass with lots of distorted hi end. But, if i take the same headphones that sound shrill and distorted and power them with a decent headphone amplifer, then the umpf, bass, bottom end is there and the sound is well balanced without that distorted top end.
I have been reading about headphone amps and some amps are better suited for high impedance headphones(400-600 Ohms) and some for low impedance headphones(10-30 Ohms), but this is not the whole story.
Some headphones require a higher wattage amp to deliver good dynamics.
I've read somewhere here on the forum where Cliff wrote that the headphone amp in the Axe Fx is not suited for too low impedance headphones.
If you try a separate headphone amp then connect it to the line out from the back of the Axe. Try different amps too and different headphones.
Many salesmen have unfortunately no idea what they are selling.
Trust you own ears!
Report back please.
Ps. Check
HeadRoom: Headphones: Full-Size, In-Ear, Wireless, Noise Cancelling, Headsets where you can write and ask for advice regarding a proper amp for your headphones, and requirements for correct amplification.
