DAC - TV To PA System

Good morning smarter people than I,
So, I'm attempting to run my Samsung 7000 series, smarter than me, TV thru my PA system. I've put together a very nice little music room which is where I entertain when friends and family stop by. (keep the animals out of my house) I have purchased a couple 20.00 to 30.00 Dac's with no luck, all I get is a faint hissing sound. I don't have top of the line equipment, but it's good enough for this old musician. I am attempting to hook up the Samsung TV to my Mackie ProFX16 board. From there I'm going into my powered Alto subwoofer and out to my powered Mackie speakers. The PA sounds great when the band is playing or when I play streaming music, etc.
With that said, do I need a specific DAC, or do I need to spend more money to get a better quantity unit? Any and all suggestions are welcome.
I don't know your equipment, but I did look up Samsung TU7000. It has an optical digital output. You should be able to connect that to a DAC that has a toslink/optical input using a toslink optical cable. You might need to go into the TV's menu and set the sound output to external/digital/toslink etc. Connect the analog L&R RCA outputs to your audio system using an standard RCA interconnect cable. It should work. I've done similarly many times in the past.
I have found info on 7000 series as well. Yes, I have hooked up the dac's via toslink optical cables into dac, out with RCA's and have the correct output setting on tv. I have hooked up many tv's and PA systems and never run into this issue. I'm guessing there is a difference in dac's because others have successfully implemented this type system. Suggestions??