[Misterer]

Hello,
 
ATH-A900s were my first decent headphones which I still use but they're old and I'm considering replacing them with something better (nothing crazy expensive though). What I'm looking at right now is the HE-400 which seems to be reasonably priced and is getting good reviews. Would you consider this to be a worthwile upgrade? I'm a bit worried of losing bass going from closed to open cans. I just don't want to be disappointed, I guess.

 

[PurpleAngel]

I believe the ATH-A900s are not really bassy headphones in the first place, so my guess is chances are just about any headphone you choose for an "upgrade" will match or better the A900 for loudness in bass.
 
What sources do you currently plug your headphones into now?

 

[Misterer]

What sources do you currently plug your headphones into now?

 
Directly to my sound card (X-Fi Fatality Pro).

 

[rubinstein]

I recommend HE 400. HE 400 has enough bass. But you may need a dac/amp. E17 can easily drive HE 400. If you buy used HE 400, make sure that they are rev 2 (white grill ones).

 

[PurpleAngel]

   
Directly to my sound card (X-Fi Fatality Pro).

You might consider selling off the X-Fi Fatal1ty Pro and getting the Creative Sound Blaster Z (SB1500), $100.
The Z comes with a headphone amplifier and a better DAC chip.
 
It might(?) end up improving the audio quality of the ATH-A900s enough that they will last you a little longer.

 

[Makiah S]

I think you'd find the HE 400 as a nice upgrade to a A900x. I had the A900x, it was simmilar to the HE 400, boosted bass and treble, however the a900x had slighty boosted upper mids, and the HE 400 has boosted Lower Mids 
 
Non the less... with a Tube I think a the HE 400 would defeat the A900x in all ways possible