The Bryston DAC chip we use is a hybrid multi-bit delta sigma DAC (digital to analogue converter) device. Before the digital data reaches the delta-sigma modulator, it is run through an 8x over-sampling process and digital interpolation filter. Due to the inherent over-sampling process of a delta- sigma modulator architecture, the overall interpolation ratio of the device is 128 times. Over-sampling and up-sampling have some great benefits when implemented correctly.
There is a significant difference between up-sampling and oversampling. Over-sampling is when the samples are repeated (2x, 4x, 8x, etc.) to create a new sampling frequency. The new samples are then generally run through an interpolation filter to create a more analog-like waveform.