olympus c50 cabinet

what are these cabinets made of?? thank you 'rocky 1313 .
According to the 1968 catalog, detailed construction blueprints for C50 were available from the factory, so it's likely that one of purveyors has scanned them for reproduction and sale.

Pacific Stereo made a plywood knockoff called "Colossus," apparently from those drawings, which is also suitable as a model.

Your major difficulty in building DIY Olympus is the fretwork grilles. They're just a box with pseudo-Asian overhangs without those.

To answer your question, 3/4" with lock-mitre joints and not enough bracing.