I just ordered a pair of polk monitor30s and a mini amp from amazon.. and i'm planning on using this set on my computer.. the question is that do I really need a DAC in order for the sound to be good?? i'm a total noob on hi-fi.. and if DACs are necessary then which one do you guys prefer for entry level? I also planning on getting a mini tube amp for the future for my monitor30s.. probably $500 is the most i'll spend.. any good tube amp suggestions also?? Any help will be very appreciated!! thanks

You don't need one, but it will have a lower noise level than your computer's onboard DAC. Even a cheap upgrade like the $30 Behringer UCA202 would be better.

Thanks for reply.. So basically does that mean i dont need a sound card anymore if i have a usb DAC??
 
EDIT: nvm obviously no lol.. anyways may this little dac sound better than internal sound cards?? because my mini amp also have analog inputs, is it better to use analog input than the 3mm jack?

You really don't need to start 2 threads on the same question:http://www.head-fi.org/t/569526/do-i-need-a-dac-in-my-situation#post_7720280
 
I strongly suggest you read up on what DACs and amps do, and what soundcards do.

A sound card is a DAC. With your ASUS Xonar DX (why oh why did you make two threads?) you won't need an external DAC. Use a 3.5mm->RCA adapter plugged into the card's line out and the amp. The Xonar DX is a very fine DAC and there's no reason to get anything better right now (if ever).

Thx for the replies.. btw sry for making two threads with the same question.. i was not sure which one will be the right place to post.. anyways i'll definitely look into DACs and probably get one in the future when i have more experience.. seems like peoples are getting good results from standalone DACs and that made interested in them.. again thx for replies, i'mma mess around with my setup first and hopefully everything will turn out good..

The Xonar itself is a pretty good DAC, but i think it's most game driven than for music.