I had that same problem yesterday with the game locking up at the amps. I had downloaded and installed a d3dx9_42.dll file in the rocksmith folder, like you're supposed to, but it turns out the dll file I found was no good. I downloaded a new file from a different place and it worked out for me.
Also, your device could be set to low volume, try plugging in your cable, go to control panel-- sounds -- Devices -- and you should see 'Rocksmith USB Guitar Adapter' right click it and see if you can turn up the volume.
I had that same problem because I had a bad version of D3Dx9_42.Dll installed. Make sure you have that file and it's in the rocksmith folder, if it is there already, try downloading it again from a different source. I found a link in the forums, but idk exactly where.
Idk, but I would suggest turning your volume down quite a bit and calibrate again with the volume low, after calibration is over, turn the volume up. It should make it seem louder.
I found the hangup. There is more than one version of D3DX9_42.dll. I installed the wrong one about 9 times. I found a link in this forum somewhere to a good DLL file. Problem resolved for me.
I'm on PC, I can see my CDLC songs, but they crash after tuning. I have tried updating direct X, downloading and inserting d3dx9_42.dll, repacking CDLC files, reinstalling the game, and everything else I can think of. I would really like to play these CDLC songs, but I have no idea what the hang up is.