Zenith Model S-829, 1935.   Most Zenith collectors want this 7- tube, chrome-grilled set and it is a tough one to find. According to the book “Zenith Radio: The early years” by Cones and Bryant, all of the chrome front models were designed by Rosenow and Company, a Chicago based industrial design firm.  This piece is a true “S” model, which is even more rare than the regular 829. The “S” prefixed model, according to famed Zenith collector Martin Blankinship, seems to indicate an expansion of shortwave coverage.  It features a superheterodyne circuit, triple-filtering, an 8-inch dynamic speaker and sold for $69.95.  This radio has all four original black lacquered wooden knobs with the chrome ring inserts.  Very good reproduction knobs are available today, but original replacements remain incredibly elusive.