Try getting some good headphones, (I don't know how those you suggested are) and a Vox amPlug AC30.

Im not sure tho.
Wait for more replies.
Follow the smoke toward the riff filled land
Make sure that the 1/4" converter is mono. coz cubes phone out is mono. so unless you want sound from the left headphone speaker only, make sure.

But all in all its a pretty good pair of headphones.
Ibanez RG321MH - PearlBlue (Now with EMG 85 and 81)
Jackson JS30RR - Black
Ibanez RG321MH - Black (now Red)

line 6 POD x3
Boss NS-2 (unused)
Ibanez TubeKing TK999HT (unused)