Need more heaphone volume from your VCI300?
Get one of these;
http://www.fiio.com.cn/en/showproduct.asp?id=309
I grabbed one of these off ebay a couple of weeks ago, & used it for the first time last night.
It does exactly what it says on the tin! …I can now use my VCI 300 with sensible headphone levels, & it charges over USB!