This article is the first of a series detailing the design and build process of an Arduino controlled Dual Mono AK4490 DAC by DimDim:
The design goal was to do a dual mono design so as to maximize SNR and channel separation. A 4-layer PCB design was chosen so as to have a very solid, low impedance ground plane as well as proper power and signal planes. The I2S, audio signals and power after the local LDO regulators are routed on the top layer, the 2 middle layers are ground and power planes, and the bottom layer serves to route I2C signals and some power lines.
See the full post here, Dimdim’s blog.