As any expert-level users will know the layouts of the Printed Circuit Board (PCB) and the ground paths’ placement also have significant effect over the sound performance.
Interference between circuits due to common impedance ground paths
As shown in the above diagram that point A, B & C are not all at zero potential due to the existence of ground impedance (R1, R2 & R3).
Potential of A with respect to ground is: VA = (I1 + I2 + I3) R1
Potential of B with respect to ground is: VB = (I1 + I2 + I3) R1 + (I2 + I3) R2
Potential of C with respect to ground is: VC = (I1 + I2 + I3) R1 + (I2 + I3) R2 + I3 R3
To reduce interference arising from common impedance ground paths, the design of DAC2488 separated all low-level analog grounds from the digital signal grounds and terminated them at a single designated point on the system’s ground conductor. By doing so, the ground potential of each circuit is just a function of its own ground current and impedance. In addition, because the common impedance ground path is connected to many circuits, the impedance of this path should be kept as low as possible to reduce harm and interference.
Harm and Interference can be minimize by separating ground paths/system