It's a cheap one I got from Radioshack, so I'm not 100% sure either. I guess i need to analyze the schematic and board to determine the amount of gain if there is an amplifier, correct?

I'm trying to wire up USB sound, but having trouble deciphering what wires go where. I'm running the 5v, G, D-, and D+ to the USB breakout but having trouble on the other side. Do i wire up channel L and common to an amplifier then to the speaker/headphone jack? Or do I go without an amplifier. I'm ...