The DVI and HDMI ports on the back of the card itself outputs audio and video. This feature was implemented since the Radeon HD 2000 series.
Because of this, you can simply use a DVI-to-HDMI adapter and get both sound + audio through.
Now, DVI and HDMI are essentially the same thing. Both Digital signals, BUT DVI is only video...while HDMI is audio + video through one cable.
If you connect to your TV via DVI (if your TV has a DVI in) you won't get sound out of it.
If you are only connecting your HD 7750 to your TV, please use HDMI so you get audio pass-through.
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