possible solution?
Here a quote from the Manual:
"Use only the enclosed USB cable to connect the US-122 and the computer......... the audio input and output will not work properly and the sound level will be inaudible or very faint."
Could this be the problem your facing?
I'm not able to get anything from my Tascam and I don't have the original usb cord, so I'm thinking that might perhaps be the reason, it might be what is causing the quite sounds on your recordings too.