When connecting a Blu-ray player to a non-HDMI receiver, how can analog...

Your Blu-ray player will decode and convert HD formats into PCM and send it through analog cables to receiver. Optical or coaxial are not enough bandwidth to transfer the signal to receiver. This is the same as SACD, you have to use 5.1 analog cables output from DVD/SACD to receiver to get HD sound of CD. It not limited to DTS or Dolby Digital, that's why it is more expensive than Sony BDP-S350 ( same features ) because of 7.1 analog outputs, with this feature you don't have to buy a new receiver with HD decoder on board, you can the old one to get HD sounds and save money.

Your new player has the decoder built in. The BDP-S550 will decode the HD audio formats internally and use the 7.1 analog outputs to send the audio to the receivers 7.1 inputs (if it has it). This means 8 RCA cables running from the Blu-Ray player to the receiver. When you want to watch Blu-Ray you will select the 7.1 input. It may only have a 5.1 input in which case you lose the surround back channels. The main competitor to the BDP-S550 is the Panasonic DMP-BD55K and the Panasonic is rated higher for picture quality and is the only one that handles every kind of pull-down cadence and also has the analog outputs for HD audio. If you still have the choice to return the Sony the Panasonic is available for $321 here http://astore.amazon.com/ewarehouse-20/detail/B001GAOYCI?
Its not a big difference between the 2 models but if it also save you money it might be worth it. Have fun.