I actually just got one of these as well, except I ordered it off of ebay from China for 20 with free shipping. Only took 9 days to arrive in mass from when I ordered it, and it works perfectly, so I guess I can't help you. I did notice the 3.5mm input was fairly noisy, so I use a y cable from my computer into the rca's. works fine with my CD changer and I-pod's etc..
I guess you're just unlucky and got a bad batch. quality control is always the issue. I would think ordering from parts express would be better, guess not. I got mine through the "hossen" seller from Hong Kong I think.