I got the http://r.ebay.com/PJHGtm, they sent the 25W version instead of the 15W. I can't hear a difference with it plugged in, I'll measure the ripple voltage and spectrum of noise between different setups later. In the mean time I used a multi USB port charger...

I am also interested in if the batteries is replaceable. Also if there is some tests of defect/shorted/"old" batteries and continued use of headsets with external power.

I tried to use a multiport USB charger driven off 220VAC and the noise is almost gone. I guess I have a notorious noisy USB system on my PC and screens. Also this is what noise you will have on USB with a Asus Xonar U3 plugged in and running an SDR.

Ah, you wrote charging noise. I have not thought about that, I took it as granted that a product like Kannon would be usable under charging if the power source was clean. I have a battery bank somewhere, will test with that as soon it's charged.

I was thinking about this one http://r.ebay.com/PJHGtm. I won't buy the more expensive ones because I can just modify the cheap ones if they are not up to the task.

Backer number 96 here. I got my Kannons yesterday and are very pleased with the sound, just what I needed for a lot of the music I listen to. It's nice to be able to listen at a lower volume and relax instead of getting fatigued by playing loud on my old headset (Beyerdynamic DT700). Only thing...