The power supply of any high-fidelity audio system must be carefully designed and well regulated in order to provide a quiet and clear background for musical performance. Despite its high efficiency, the high frequency operation and strong magnetic field of the switching power supply have made it unsuitable for audio applications, as it will introduce a great deal of noise and interference to the system.
In the design of DAC2488, the performance of the high quality power supply is further improved by multiple steps of linear regulation. Many designs employ ceramic or silver mica capacitors as high frequency bypass capacitors, which will establish an AC ground that is good into the 100MHz region. Unless additional loads are driven by the analog outputs, additional capacitance usually is not necessary. If additional capacitance is required then a 10 to 47F tantalum types will suffice in most cases. Having said that, the final decision as to the amount and type of capacitance should be made when the circuit board layout is finalized.
The analog portion of the system required positive and negative power supplies to operate. With the op-amp, it requires ± 12 to ± 15V for operation. The picture below shows a typical Bridge Rectification circuit; and it is commonly used in voltage rectification.
A typical bridge rectification circuit
In the DAC2488 design, high performance audio grade components such as the Mallory- Jamicon 25v 4700uf Axial Capacitors, LM317T/LM337T regulator, Sanyo 125C audio capacitor and Dale/Vishay 0.1% accuracy resister are used in each channel to produce an outstanding sound performance.