I just discovered my second-hand laserdisc player was previously modified to pass the RF AC3 signal, so now I need to go the next step and decode that RF for 5.1... I know the RF demodulators go for $150 and up on eBay, but I'm also intrigued by the possibility of finding an older receiver with the demodulator built in. I've read that some of these receivers will output the individual channels (for those with external amps, I suppose?), which would be a nice bonus. So what I'm wondering is - what older units should I be looking for?