So it sounds like you really don't like the sound of using your DI inputs on your M-Box due to their inferior nature? But you like the preamp section better on your Mackie? Well I hate to inform you of this, you would glean a better signal if you take the Mackie balance line level output to the balance line level input on your M-Box. You may even have to engage the pad on the M-Box? So the key here is to get your output level up on the Mackie and reduce and/or pad the input level to the M-Box. This will bring your signal to noise ratio & headroom into their proper ranges. To be honest with you, I am not really wild about the input sections on any of the M-Boxes by Digi design. They're not good. They are fraught with problems. All I want is a transformer isolated input to the analog to digital converter and screw the rest of their electronics.

I don't know anyone that likes their Digi design microphone preamps?
Ms. Remy Ann David

Using the balanced inputs and getting the gain staging correct in the configuration described should eliminate the hiss problem, but it's not going to do much for the quality of the sound. The line-level inputs on the Mbox are simply attenuated and put through the mic pre-amps, so you get the double flavour of the Mackie convolved with the Mbox. Taste nice? Not to my liking.

Thank you so very much for your input!! That kills me of course, the quality is definitely not good, but right now I trying to work with what I got!! In the near future, I will be able to drop a few $$$ on some gear, but must continue working in the mean while! ! I appreciate the help a lot!Thanks!