B
Beck
Guest
Awesome outcome! 

Check the back of the machine. There is a switch which sets the input level of channel 8 (because it is often used for carrying timecode data rather than audio). Make sure it's on -10.
Just to check, with DBX - make sure you are both recording and playing back with it enabled. Also, going into the red with DBX can cause weird effects, but with the extra noise floor you shouldn't need to.
To be honest, I always use DBX on mine, and I didn't really like the extra noise when I tried a session with it off. But I guess it's ultimately a matter of individual taste.