Thankyou for clearing my misunderstanding, i use the sony experia z3 and tried hiby music it works but only for music installed, thanks
From what I've seen on the Internet, the Xperia Z3 should work without any special apps. I mean, even if you're watching Youtube, the sound should automatically go through USB (if Q1 is connected). I might be wrong, but hey - it's not that expensive to pay $1 for a cable and just try it out
And I just saw your other post - no, the amplifier is a critical component of any audio equipment, and it does not include a gain switch. The switch is just an addition.
An amplifier basically takes the input waveform (coming from a DAC) and modifies it with higher output current. The main component is a tube triode, or NPN transistor, if you know something about electronics, you can imagine how it works (of course there is much more to minimize noise and improve fidelity). Listening to music without an amplifier is basically impossible, because it's either very silent or very distorted. Your phone has a built-in amplifier, too, but it's of quite bad quality compared to Q1. So, when you turn the volume up to 100%, it's very probable to hear background noise and other 'disturbing modifications' to the sound that you probably don't want. That's because it takes the low-volume audio, and feeds it to the built-in amplifier. The more you try to amplify (read: make louder) the sound, the more distortion and noise it adds. Now if you use an external, high quality amplifier such as Q1 (connected through the headphone jack) you can leave your phone's internal sound bar at the lowest possible volume (might need to set it 1 step higher, actually) and amplify the sound with the Q1. That way, you still get an amplified (louder) sound, but avoid adding any noise or distortion - that's because your phone's internal amplifier is used as little as possible, and it changes the sound coming from the DAC as little as possible.
So, in other words, a DAC outputs a very low-volume sound, and an amplifier just makes it louder. The worse the amplifier's quality, the more noise it adds.
About the DAC part - it converts your digital data (read: music files) into sound. The better quality of the DAC, the more the output is similar to the original recording. So if you wanted to have a music file that sounds
exactly the same as in a live concert, you would need:
a) a very good microphone (i don't really think such exists to this day) and ADC (analog-to-digital converter) - to record it without mutilating the sound and store its properties in a computer/storage media
b) lossless audio codec such as FLAC, or uncompressed audio - to store the audio in a computer without modifying it by compression
c) a good DAC - to re-convert the sound back to audible format (something that you can hear) as exactly as possible. Note that even with the most expensive DAC, there is still a margin of error, they can't reproduce a waveform that meets every single bit of data sent to it. There will always be some differences if you put your file through a DAC and then straight back into an ADC. You will never get the same file by doing this.
d) a good amplifier - to make the output of the DAC loud enough to actually listen to it comfortably. It must be good because bad quality amplifiers add noise and distortion.
e) good headphones, of course.
Of course you can't get the perfect ones for each of these categories - it would just be too expensive. But you shouldn't buy the most expensive headphones, or the most expensive DAC, pair them with the cheapest amp and expect the setup to be significantly better than your current one. It won't.
It might seem that I went off-topic with this post, but I just wanted to emphasize why you need to have different parts of similar quality. So, if your phone's DAC is decent enough, but its amplifier is bad, you can connect your Q1 through the headphone port and it will probably be just as good as if you did it through USB - because the DAC is good enough anyway. Especially if you don't have very expensive headphones that can actually let you hear the difference. The point is in finding your
weakest point and upgrading it - upgrading the other components might make the sound
slightly better, but in my opinion it's a waste of time.
Now, of course you don't know if your phone's DAC or amp is the bottleneck, and that's why I wanted to suggest you to try both ways and see which one works best for you. Connected through headphone port, the Q1 should have a longer battery life, so if you don't see any difference between these 2 modes, you can just use it as an amp, some power.
I hope this wasn't too long, and even more that it was actually helpful to someone
If anyone is reading this and thinks that I'm wrong in one way or another, please feel free to correct my mistakes - I still consider myself a newbie here and I don't own enough equipment to have anything near a professional opinion. I just wanted to share what (I think) I know by now and possibly help someone decide.