Another good source for inexpensive Dolby Digital would be to use a receiver as your source. Most of these have 5.1 channel pass-throughs that remain unprocessed in the digital domain. I would recommend you look at the Outlaw Audio 1050 receiver. You can get one new for $500 from there website or sometimes find used ones for $350-400.
http://www.outlawaudio.com
The cheapest pre's that I have seen used are the Harman Kardan Signature 2.0 ($450 at ebay or audiogon but they all come from ubid.com) the sony tae-9000 (I think is the number also comes from ubid originally then to ebay and audiogon $700), and the Legacy Audio (is a proton) pre-amp that was selling on ebay for $275. I use a Denon 2801 as my pre (with rotel amps) and am happy with it until I can afford a dedicated system. Another idea would be to look for a older rotel pre that has a 25 pin connector and connect it to a rotel dolby digital decoder (about $500 for this but the goods are a little older). If you are concerned about ground loops then I would recommend the monster series of power centres hts 2000 or 2500. They can be had for 110-170 on ebay and they eliminated the cable ground loop in my system (this was the only product that would do it as I had cable that was not installed properly).
Patrick
http://www.outlawaudio.com
The cheapest pre's that I have seen used are the Harman Kardan Signature 2.0 ($450 at ebay or audiogon but they all come from ubid.com) the sony tae-9000 (I think is the number also comes from ubid originally then to ebay and audiogon $700), and the Legacy Audio (is a proton) pre-amp that was selling on ebay for $275. I use a Denon 2801 as my pre (with rotel amps) and am happy with it until I can afford a dedicated system. Another idea would be to look for a older rotel pre that has a 25 pin connector and connect it to a rotel dolby digital decoder (about $500 for this but the goods are a little older). If you are concerned about ground loops then I would recommend the monster series of power centres hts 2000 or 2500. They can be had for 110-170 on ebay and they eliminated the cable ground loop in my system (this was the only product that would do it as I had cable that was not installed properly).
Patrick