Headphone Amp+DAC vs Onboard Op-Amp?

[jkteddy77]

I just got this Amp_Dac for my DT990 250ohm headphones:
http/www.monoprice.com/Product?c_id=120&cp_id=12008&cs_id=1200801&p_id=11567&seq=1&format=2
It is a remodeled Fiio E09K + it has a DAC in it, so it is quality made and is suppossedly 15-600ohm
I also see "Output Power" on the specs of the amp:

what does this mean? the impedance rang says 16-600, but the two output powers say 32 and 300 ohms?
Asus never gave out the Impedance range of the Op-Amp on my Asus Z97-Pro, even on their page for my mobo:
http/www.asus.com/us/Motherboards/Z97PRO/
but right now, the Desktop Amp set into Gain mode (could this be the two separate output powers on the graph?) at 80% of its max I'd day matches what my mobo can do. And Both are way too loud, I keep my PC at 50% through the Op-Amp and that is comfortable listening... Do I even need this amp? is it supposed to make it sound better?
These are only 250ohm headphones, how could I nearly be maxing out this apparently 600ohm amp?

 

[theLeggo]

a headphone with a 300 ohm impedance is going to get 150mW of power. a headphone with a 32ohm impedance will get 900 milliwatts of power. An amp/dac does more than just power your headphones, they can help clean up the sound. With the DT990's you can drive them probably to a loud lvl with your motherboard, but that doesn't mean it will help the sound more than the monoprice amp/dac.

You need to let your ears adjust to the monoprice amp, and you probably don't need the gain switch on. After a few days of consistent listening, go back to just your mobo sound. Try to listen for differences then. If you don't hear much of a difference return the monoprice amp. Remember your ears and brain have to adjust to a sound, the only time people really notice a difference is with a completely different sound signature, which an amp/dac probably won't be doing until the $250-350 range with OTL amps vs solid state.

 

[jkteddy77]

a headphone with a 300 ohm impedance is going to get 150mW of power. a headphone with a 32ohm impedance will get 900 milliwatts of power. An amp/dac does more than just power your headphones, they can help clean up the sound. With the DT990's you can drive them probably to a loud lvl with your motherboard, but that doesn't mean it will help the sound more than the monoprice amp/dac.

You need to let your ears adjust to the monoprice amp, and you probably don't need the gain switch on. After a few days of consistent listening, go back to just your mobo sound. Try to listen for differences then. If you don't hear much of a difference return the monoprice amp. Remember your ears and brain have to adjust to a sound, the only time people really notice a difference is with a completely different sound signature, which an amp/dac probably won't be doing until the $250-350 range with OTL amps vs solid state.

It is only slightly cleaner sounding... The only reason I invested in the Amp+Dac was to get it louder. when connected to my mobo, they sound almost the exact same. I get very little noise from my mobo's op-amp. I have used the amp for a few days now and hear nothing but a slightly louder signal, not much cleaner audio. I cannot tell a difference even when using each for hours in between before trying the other.
I'd actually also need the gain on as well since with the gain off, even with the Monoprice Aamp at max volume, it doersn't match my onboard audio... the specs box in my original post and in the instructions recommend gain off only for low impedance headphones like 32ohm or less.

I did find out that my Logitech Z506's have a built-in amp in it as well, and that gets just as loud or louder than the Monoprice amp, but as expected, is a little bit noisier due to the fact that it is going from my PC, through the sub, and then into the speaker with the jack in it.
I am returning the Monoproce Amp, and don't know what to do now... I do not feel like investing into an Amp or Dac or both that cost more than the freaking headphones themselves.

 

[theLeggo]

if you are satisfied with your motherboard sound, then stick with it. Guys over at head-fi can maybe lead you to a different solution, but honestly if you don't want to spend the money, don't.