The Audio Out : 1 (Side / Hybrid w/ HP) is a 1/8" stereo mini jack, so all you need is a cable with a 1/8" stereo mini plug on one end and RCA's on the other. Then set the Fixed/Variable in the menu just like your older Sony TV.
Another option is to use the optical digital audio out to a basic 2 channel DAC, then from the DAC to your preamp. It will be necessary to set the digital audio out to PCM which, after looking at a manual, appears to be possible.
If you don't currently have a DAC with an available optical input, then the first option works for just the price of the adapter cable.