It is a good procedure to use DIP sockets for IC so that you can try replacing the chip with new one(if the chip is bad), and you can take them out to use for other projects later as well.
Also testing the whole thing on a breadboard fully before assembling is preferred so that you can attain the confidence for building.
There are alternative debugging procedures out like:-
*) Leave the USB , power it using a 6V battery.
*) Step by step method: Remove stereo pin and test the individual inputs using some other sources, and finally both simultaneously.
Next time post that you hit on success