Servus,
Will I notice a difference if I connect my PC speakers (jack) to the amplifier instead of the onboard sound card? The GSX 1000 is more or less an external sound card, isn't it?
This will certainly depend on the speakers. A good sound card does not turn bad speakers into good ones. I had a small receiver with normal B&W speakers connected to the Sennheiser and the sound was very good.