I bought this little mixer especially for using it as an external sound card, to connect my guitar to PC. First of of it is laggy, the latency makes is unusable for this purpose. Second, if the line signal comes for USB(output from pc), it is sent again as input from the MIC input, creating a strange and infinite feedback. I`m still to understand the point of this feature, but i did not managed to make my way around it. Anyway, i ended up using it as a regular mixer, powered by USB instead of wall socket, and it works fine in that sense.