This is a fantastic find and a great surprise in terms of sound quality and peculiar construction techniques. Design is funny and clever, bended Plywood , cherry finishing adds warmth to the picture. After a good restoring for old capacitor and a quick  check for the Tubes wear, contact cleanings, the tuner is supplying a smooth and not fatiguing sound with astonihing tuning stability thanks to the Variable Permeabilty technique rather than the most used capacitor.