I have a 2.0 powered speakers that where previously connected to a non-smart-tv audio output and to a pc 3.5mm audio output. At that time the sound was really great and when we watched Netflix and movies from the pc we really enjoyed the sound quality, it was loud, rich and detailed.
The old tv and pc had died, and now we purchased that new Q80T smart tv, which doesn't have an audio out but an optical one. So I connected it to a simple DAC via the optical and to the speakers via rca. Also I set the tv audio to PCM setting. Well, the sound isn't close to what we had before, it sounds really "flat" and has a lack of bass and detail when watching movies, and also when playing music in Spotify the sound even gets distorted at high volume.
I've seen posts of people who say that the optical outputs of the new Samsung TVs are limited and can't deliver high quality sound, and for example it won't output digital data at higher than 48 kHz or even 24bit. And the only way to get the full potential is from the eARC HDMI output.
I was thinking of buying a new decent DAC to replace the simple one that I owe now, but now when I realized that the optical output itself is limited, I doubt changing the DAC will help to improve the sound quality.
I really regret of buying this TV which forcing me to get rid of my speakers or spending a lot more money for a eARC compatible device