I have refurbished (changed) the plywood cabs with white birch (250$ job years ago) along with the insides (by speaker saver IN LAKE WORTH =another 250$) and have owned them a long time - I am using them with McIntosh ML 2c and ML 1c. ON / OFF electric switch provided. Schematic also provided via PDF.
WHITE BIRCH CAN BE STAINED - BETTER HARDWOOD FOR SOUND IMPROVEMENT and looks