"Purchased a SPDIF cable and linked from OPPO to Hegel so can get sound from Tv/streaming, blue ray etc. but no sound what so ever.I presume I am utilizing DAC from OPPO? Is this correct?"
No. You're not using the DAC in the Oppo. I know that it can be confusing if you're new to setting this stuff up. You have 3 DAC's right now in your system. One in the PC, one in the Oppo and one in the Hegel. The key thing to remember is that you are only going to use 1 of them, and that will depend on what you are trying to do. The easiest way to visualize it is to follow the music. The reason you need a DAC in the first place, is to convert the digital signal to analog because we don't have the ability to listen to music in digital like a computer. For our ears to listen to music, it has to be in the form of analog. If you were to plug a pair of headphones into your computer, and listen to music, you would be using the DAC in your computer.
When you are connecting your PC directly to your Hegel, what kind if connection are you using? It can be done 2 ways. You can run a cable from your headphone jack on the computer into a regular analog input on your Integrated. Doing it this way is using the dac in your pc, and it's connected to your amp just like you would a tuner or cd player. The other option is to run some type of digital cable from your pc to the dac in your Hegel. Doing it that way would bypass the dac in your pc, keeping the signal digital, and then use the dac in the Hegel to do the conversion to analog. Before we can go any further, we need to know how are you connecting your pc to your Hegel, digital or analog?