"Will reverting to M2tech Hiface 2 + a new digital RCA cable connected to SPdif input of the DAC provide better sound from my PC than a High End USB cable connected to USB input of the DAC ?"
Yes. The Highface is designed to designed to reduce jitter. It allows you to bypass the clock in your computer, and use the clock in the Highface. It should give you a noticeable increase in sound quality.
You don't have to buy a very expensive cable either. Something like an Audioquest Cinnamon would be a good choice. You can probably get one in Best Buy. If you don't like it, you can always return it.
Yes. The Highface is designed to designed to reduce jitter. It allows you to bypass the clock in your computer, and use the clock in the Highface. It should give you a noticeable increase in sound quality.
You don't have to buy a very expensive cable either. Something like an Audioquest Cinnamon would be a good choice. You can probably get one in Best Buy. If you don't like it, you can always return it.