PJABBER
100+ Head-Fier
The sound has its issues, maybe just with the supplied 1.01 firmware, if you turn the volume right down to 0, you can hear the noise floor which toggles when you play/pause. This sounds more like a hardware/Amp stage issue to me.
The unit pops every time you change track, irrespective of the gapless setting. The S5 has a quick fade-in fade-out which I prefer.
The battery is much poorer, I get around 18 hours from the S5 and about 8 from the T6 with a range of MP3s, mostly 320kbps.
I mentioned the possibility that the T6/Rocker has a noise floor in my first post write-up but I personally could not hear it, while a teenager that has one of the units I bought does. We did what you describe, played a file and brought the volume to 0. Seems most apparent to him in ear buds so it might also mean that very low impedence devices are most subject to it. But, he does hear noise on a number of the devices I have been testing, with the notable exception of the Sansa Clip+. Sansa did a great job with that device, still hard for other manufacturers to match it for quality and value.
Someone suggested using an added in-line volume control - to bring that control to low volume and then raise and lower the volume of the device to adjust the sound for listening. I guess that adds an element of impedence and eliminates or minimizes the noise. I haven't tried this myself.
I have been tracking worldwide reviews and the slight pop in switching songs was mentioned in a very few reviews. Those listeners don't find it obtrusive but it might annoy some, like yourself, that can hear it.
Both the perceived noise floor and the file transition soft "plop" that you describe have been referred to both Benjie and AGPtek for review. Might be a fix forthcoming but who knows when it might be addressed.