I've been reluctant to let it be known here that I don't own a DAC. Uh oh, now I've done it. No more respect for me.
If you plug your headphones into the headphone jack of your cheap notebook computer and don't ever hear any noise, and if so far as you can tell you never hear distortion except once in a while when you hear a sound that is most likely the sound your headphones make when you try to make them play louder than they want to play, would there be a genuinely good reason for you to go out and buy a DAC?
I need to say something to earn back some respect. I recently bought, from an eBay seller, a mid-80s digital multimeter. Not just any. A Fluke 8060A. It will measure signal level (volts) with very good accuracy as high in frequency as 50 kHz. The norm for the great majority of DMMs that you see in hardware stores and online is 400 Hz, which means that the great majority of DMMs are useless for audio frequency measurements. Most of these older Fluke meters have been beat all to hell, but I lucked into an exceptionally good one that looks and performs like it just came out of the box. I just can't tell you how cool it is. Instead of having the now-ubiquitous rotating knob that visits all the settings you don't want while you move it to the setting you want, it has a row of big sturdy push buttons along one edge. Two of the buttons are used for selecting the function, giving four possible function settings, for current, volts, resistance, and diode test. Another button the same color as those two selects AC vs. DC. The other five buttons are a darker color and they select the range. Direct access to every setting. True RMS readings of course. It also measures frequency of course. It is very, very cool. Every time I pick it up I, well, let's just say that it's a cool toy.