Nimzerz
1000+ Head-Fier
Congrats! I myself had to go through that tough decision, and decided on the HE-500 even though I am still not driving them with nearly anything. No proper DAC and no proper amp, but I can still see the potential by using them ever so often with my parents' Denon receiver. I hope you enjoy the HE-400 and TBH, if you think the bass is not more than satisfactory for you, then maybe consider trying a pair of HE-500's before you decide to upgrade.