So I've had these for a few months now and oh man do I love them
Love how I'm able to listen to such a variety of genres which all sound great.
One question, I want to get an amp but not sure what to get, doesn't need to be portable. What worries me is when people say they can't really tell any difference with on. Maybe the integrated sound card on my desktop is incredibly weak but it can't drive these very well at all, unlike my laptop with inbuilt amp.
So any recommendations?
I've had these headphones with the longest usage out of my entire rack. 3000+ hours with different sources, in fact they are my first "audiophile" pair of headphones. I still try a bunch of earpads with it such as the Alpha Pads and HE-400 Pleathers. I modded the wings for them to have a tighter spring.
DAC's and Amps with the A900X
***Please do note that these are very incremental changes and you may not notice an immediate difference. Your ears will adjust to the new sound signature, and if you change back to your previous source change. You will notice the change for better or for worse.
The Dac:
***The DAC is what will be the only thing you need to worry about. It will depend on how solid the bass hump hits, cold/warmth of the headphone, and soundstage/imaging for the A900X.
As the A900X does not benefit from major amping if your device can meet the requirements of outputting at least 60 Ohms. The headphones only require
43 Ohms. However, the quality of the source for headphones is how stable the current is being outputted into the headphones.
Laptops may not be able to provide a steady output. Your laptop may be a weak DAC and may not provide the cleanest signal. A cleaner signal will slightly improve the clarity of the mids, slightly provide rough sparkly treble, and slightly add more texture (not quantity) to the bass.
Despite the 53mm drivers, the A900X is easy to drive.
Using a weak source not outputting enough current, you may feel:
-Sharp and uncontrolled treble (This spike will be controlled with better recordings as well)
-Weak bass kicks (Again, depends on the original music recordings)
-Congested midrange
Warm amps/dac's (FiiO Line):
-Bassier (enjoyable with bass guitars, note the warmth will not muddy up the mids)
Cold amps/dacs (I only have 1 cold source, and that's my onboard Crosshair Formula-Z Supreme FXIII Audio):
-Controlled solid bass
-Rougher treble
The FiiO E07K and A900X (in addition to Ashade's opinion of the E07K)
From my PC, I leave the E07K at 0 gain and max volume (which in this case is 60). I leave the rest of the volume controls to my keyboard. On weaker devices that cannot output enough volume, I set the E07K at +6 gain which is more than enough most of the time.
The E07K is a great sounding DAC for its' price point, it's portable and you can bring it anywhere as a portable AMP/DAC. I'm still using it until my ODAC/Objective 2 comes in the mail.
Basshead Paradise on a budget (meaning you're not willing to buy a Sony XB500 for the sake of bass). If you love techno and metal, I just know you might do this.
I DO NOT RECOMMEND THIS AS THIS CAN DAMAGE YOUR HEADPHONES
The E07K has a built in Equalizer, in which you can bump the bass all the way so the entire cans vibrate. It also has a treble option in which you can decrease the treble to lower the harsh treble if you plan to bump the bass to the max and crank the volume up.
In this scenario:
I have the treble at -6 which reduces the harsh highs when putting these on the limit
The bass at
+10. For the most bass quantity.
With volume at
60 and gain on
+6. The gain on +6 will extract the most bass detail it can out of the digital signal and I believe it puts the E07K outputting 150 ohms; pushing the a900x at its' utmost limit.
Even though it is EXTREMELY fun. I might have nicked the drivers a little in which if I turn the volume too high with the bass, the left driver makes a rattly vibrating sound.
IF YOU DO HAPPEN TO DO THIS, bass guitars don't flood the mids too much and bass kicks feel like you're really inside a bass kick drum. Along with the oh so heavenly sub bass)
I was even able to push more bass quantity out of the A900X than the Dr Dre Detox. The Dr Dre Detox's bass distorted and covered the entire mids way before the A900X got to unleash its' power.
Getting a better AMP
Unless if you plan to
push the bass to the max AND be able to hear your mids/treble, there is no absolute reason to upgrade your amp for these headphones in particular. On a regular MP3 player such as a Sony Walkman and iPod Touch, these can go quite loud.
The A900X is a
fun and balanced sounding headphone. With nice punchy and clean sounding bass, rich mids and sparkly treble. Going all out for an amp for this headphone in this particular, again; isn't necessary. The only time you need a better amp is if you're going to play these headphones at an unusually loud volume without distorting the headphones. At that point though, your ears might not be able to take it, or a driver will pop.
an improvement in my ATH A900X. 
