Essentially, a preamp is used for several things:
- As a way to switch between multiple sound sources (i.e. CD player, tape, etc.)
- Be able to provide a way to adjust volume
- Contains a circuit that has enough current to drive certain amps (sometimes digital sources do not have enough current in the analog output circuits).
You can add a preamp into the mix, but it is not really needed with the NFB-28.28. The NFB already has a volume control. You can attached multiple digital sources to the unit as well as one analog source (the IN5 RCA inputs). The current in the NFB should be fine to drive any amp you attach. The Yamaha studio monitors will have a preamp type circuit inside because it needs an active analog circuit for the crossover to separate the woofer amp and the tweeter amp. In your situation, the only reason to add a preamp is if you felt the NFB was lacking in some way. For example, if you had a CD player that was very bright/harsh sounding, you could get a tube preamp or a warm-sounding preamp to put in between. This would further modify the analog waveforms from the DAC to calm down the sound.
Honestly, I think the sound quality of the Audio-GD is high enough that you would have to spend a lot of money on a preamp to get something better than what is already output from the NFB (like $2,000 or more).
You are correct in the understanding that a DAC converts digital data (0s and 1s) to an analog waveform. Anything coming from satellite TV or CD or bluray is going to be transmitted in digital format, so there has to be a DAC somewhere. Many satellite receivers have a DAC inside because you will usually see left/right analog RCA outputs, but the quality is going to be poor compared to Audio-GD. The conversion from digital to an analog waveform is where the sound quality of the Audio-GD is superior. The power supply and DAC / analog circuits are significantly better. You can always get better than the NFB, but it will cost more. Just look at the NFB-27.77. The chassis is twice as large. Three separate power supplies (one for digital and two for analog). Fully balanced analog circuits. Over twice as expensive.
It’s not that the DAC chip should be described as powerful. You want to get a DAC that is clean/accurate. Large capacity linear power supply, fully discrete analog circuits, good design approach, etc.
On the Blue Jean 1694A, select “Digital Audio” for the application for sure. They use specific RCA connectors and the RCA connectors are different for other purposes (such as subwoofer, stereo, etc.). The cable color doesn’t really matter. I usually just get black, but you can get anything you want. Obviously, get the “RCA/RCA” connectors. Remember, 6 feet long (to avoid short cable signal reflections).
There might be a small chance that the satellite receive does not have COAX. In that case, you will probably need to use a toslink digital cable. The lifatec toslink cables are the best for the money that I know of. The length doesn’t matter.
http://www.lifatec.com/toslink2.html
Hopefully, I’ve answered everything.