Hi Jack, having recently setup my S8 successfully I am happy to assist you here 

originally I had thought incorrectly that my samsung 8000 series TV had a variable audio output but I found out afterwards that Samsung is notorious for choosing to only have Fixed audio out options only which unfortunately has alienated the headphone jack connecting market segment for Samsung which with products like the S8 is only growing. Therein lays the crux of the issue for you since the S8 is optimized for headphone jack implementations 

i happen to have two legacy amplifiers in my household, one an ADS CC4 and another a Sony, also a low profile one but unfortunately I'm not in front of it and don't have the model number handy.  The key with both of these amplifiers is that they both have a headphone jack in the front of them. The ADS a large headphone jack while the Sony one has a 3.5mm jack.  While the ADS amp is much much better than the Sony one, I ended up using the Sony one since very few of the cable TV universal remotes have the ADS remote control codes preloaded, which ended up being essential to keep things simple for our media controlling household (my wife especially).  Multiple big remotes are not tolerated in our household (apple and Amazon fire are ok). My Verizon FIOS remote was no exception and hence the Sony one ended up working perfectly. 

Ideally your Yamaha amp has a headphone jack in the front of it for you to plug the S8 into and if it doesn't you should then return / exchange it for one that does and that should get the buzz out of your system.  I hope this is helpful, good luck! 

Humphrey 

Michael,  i just saw this. i'll take a photo of the interim setup which i can only describe as a bit Mickey Mouse'ish which you'll see why, but so far I love the high clarity and detail with just the right amount of meaty clear low-end, which is exactly what i was hoping for.  The eventual setup in our new home will end up looking much better but that's a few months away. 

Humphrey