It would work on a board, but the risk of electrocution from ~40VDC PS is too great to leave the connections exposed. Even the Altmann DAC had plastic PS connectors on the DAC PCB. Only the battery terminals were exposed and should be covered for interior use. It would be better to build the wood board into a full wood box. After having built many wood boxes for electronics to save money, I will probably never do it again. The price for a good aluminum box from Par metal is low compared to the extra effort it takes to make connectors designed to mounting in sheet metal work in thicker wood. Only the IEC connector is difficult, all other connectors can be cut with a 1/2" unibit.
The full shielding does make a difference, maybe it is the ground reservoir concept, or noise shielding. The modules won't benefit from shielding as much as the outside world will benefit from shielding the noisy amp.