[Swy05]

Mods delete please

 

[castleofargh]

The way you describe it, and talk about being fast enough to take the in ear off your ears, I conclude that the noise isn't just for a fraction of a second, but lasts some time. Is that correct?

If you're going to do more tests, I suggest using the least sensitive IEM or, even better, a headphone if you have the right plug size or an adapter. And leaving them out of your ears.

The usual suspects for loud noises (no idea if they concern that device!!!) are:
-1/issue while going from one file resolution to another. Should be easy to test with a few tracks on the phone.
-2/something about contacts in your plugs when you move around, with everything in your pocket, for example). Turn, push, wiggle, and find out if that can bring out the noise.
-3/the amp section is too sensitive to the cellphone's signals or whatever electromagnetic source. My initial bet for lasting sounds, but also the least logical, considering a little USB DAC is clearly supposed to work near a cellphone, so that would mean a terrible design flaw for such a product. Might be worth using your phone in airplane mode with a few tracks on the phone and try to replicate the problem(or fail to).
-4/some static electricity building up between the cable and some clothes. Also, fairly straightforward when it comes to testing this. Sometimes it's clothes, sometimes it's the shoes or the floor. Those should definitely not last unless you move like a mad man, and only be loud in the most sensitive IEMs.
-5/that device is a lemon and has some serious problem(it can happen with any product).

A quick google search suggests you're not alone, I found loud noise brought up 2 times(no sure cause or fix).

Personally, I'd burn it with fire so it can never hurt me or anybody else again.