DAc's in televisions

Hi!
I connected my computer to my tv with a HDMI cable and the tv then converts the audio to analog. Then sends the audio through the EXT 2 (Scart) on the television to the Sterio Reciver. My question is, how much better sound will i get from an external usb dac?
My Sterio setup is not that expensive, think i paid around 200 dollar for the speaker and 350 for the reciver 10 years ago.
Kind regards Soqnic

Wait........what?

Is your receiver not digital?

How about this, what receiver do you have?