What is DS400+ work for you
Headphone Amplifier /DAC
Headphone amps, many high-end headphones are equipped with amps, and some people also add amps for low-end headphones and earplugs. So, what is the role of the amp, and what is the difference between adding it or not?

One of the functions of amp, amplifying the signal
Many current audio sources, especially those powered by batteries, in order to reduce costs and increase playback time, the output power is relatively small. 1000mW rated power headphones and earplugs are not suitable. Although when listening to music normally, the power output to the earphone is only a few mW, and the large earphone with low sensitivity needs more than 10mW, but the power here is the average power. For large dynamic music, the peak power may be 10 of the average power. -30 times, the peak power of some symphonies can reach more than 50 times the average power. Therefore, the average output power of 1mW sometimes requires a maximum output capacity of 30-50mW, otherwise there will be waveform clipping distortion. This output capability cannot be achieved for many low-power audio sources, or even more than half of the sound cards. Therefore, if the sensitivity of the earphone is not very high and the output power of the audio source is not very large, adding an amp will significantly improve the sound quality.
The second function of amp, matching impedance
Most of today’s sound cards have no headphone output jack, only LINE OUT jack. But most people still directly plug the headphones into the LINE OUT jack to listen to music, which is actually inappropriate. The output impedance of LINE OUT is very high, generally in the range of hundreds to thousands of ohms. When connected to a power amplifier or headphone amplifier, the impedance can be completely matched. It is inevitable to affect the sound quality when connected to headphones of several tens of ohms. Moreover, the output capacitor of many sound cards is only 100uF. Left and right, or even 47uF, when connected to low-impedance headphones, will seriously attenuate the bass signal. For example: a sound card with a 47uF output capacitor, connected to a 32 ohm headphone, the low frequency cutoff frequency is 110Hz, that is to say, the bass below 110Hz will be severely attenuated. At this time, adding an amp will improve the sound quality significantly.

The third function of amp, tuning function
Many people say that amps are for fidelity, and tuning is coloring, which runs counter to the goal of HIFI, and tuning is unnecessary. In my opinion, proper tuning is allowed, even necessary, for several reasons:

a. Tuning for more fidelity
Fidelity is a matter of the entire listening system. In addition to amps, it also includes recording, music production, audio equipment, headphones (or speakers), human ears, and related wires, not just amps. , if there is inevitable distortion in other links, it is possible to compensate by tuning the amp, although the amp is not fidelity, but the whole listening system will be more fidelity. E.g:
b, proper tone coloring. As we all know, the sound of the gall amp (tube headphone amplifier) ​​is better, durable and musical, but the gall amp is distorted, which is 1-2 orders of magnitude higher than the stone amp (transistor or integrated circuit headphone amplifier). That is tens or hundreds of times higher, the frequency response of the gallbladder amp is not fidelity, the two ends are low and the middle is high. However, the coupled harmonic distortion of the tube and the slightly prominent mid-frequency are not objectionable to the human ear, and even somewhat pleasing to the human ear. Therefore, many people need to get out of the misunderstanding of HIFI.