Radio broadcast .. (1922-30)

.RADIO BROADCAST ADVERTISER. Can't Beat tte S-M 720?" Just Try this All-A. C. 722— And at $74.75! Have you heard the whisperings among the fans this fall—how Silver Marshall has brought out an all-electric custom receiver design which sells, completely wired at the factory, for only $74.75 net—and yet which combines perfect convenience of operation with such extreme performance as has seldom been seen in the most complicated sets? Three screen-grid tubes, with band selector tuning—four tuned circuits in all—with screen-grid power detection—these, built up to the highest S-M standard of engineering, mean, of course, distance range right up among the top notchers. And if you think for one moment that selectivity has been sacrificed to full single-dial control—one test of a 72Z on the most powerful local in your town will give you an entirely new conception of what S-M precision in coil manufacture can accomplish! All-A. C. Operation These receivers are absolutely all electric—even the 735 short- wave set, the first of its kind ever offered on the market. Power supplies are built into the receivers—not separate. (Power supply for the 712 is built into the 677 Amplifier.) The full advantages of the new a.c. screen-grid tubes are secured. The characteristic superior S-M tone quality, distance-range, and selectivity are in these receivers as never before, due not alone to band-selector tuning but also to still greater refinements of design and accuracy of manufacture. Startling in perfec- tion of tone quality, the 677 Clough-system (Above) — three screen- grid tubes (including de- tector), band-niter, 245 push-pull stage—these help make the 722 the out- standing buy of the year at $74.75 net, completely wired, less tubes and cabi- net. Component parts total $52.90. Tubes required: 3 —'24, 1—'27, 2—'45, 1— '80. Amplifier (right) is ideal either for power- ful record amplifica- tion, or with the 712. Tubes required:!—'27, 2—'45, 1—'80. $58.50, less tubes. Component parts total $43.4O net. New!— 735 Short- Wave Receiver (Left)—a screen-grid r. f. stage, new plug-in coils covering the bands from 17 to 2O4 meters, regenerative detect- or, typical S-M audio amplifier all help to make this first a. c. short-wave set first also in performance. Price, wired complete with built-in power unit, less cabinet and tubes, only $64.90. Component parts total $44.90. Tubes required: 1—'24, 2—'27, 2—'45, 1—'80. Two extra coils, 131P and 131Q, cover the broadcast band at an extra cost of $1.65. Adapted for battery use (735DC) price, $44.80, less cabinet and tubes. Component parts total $26.80. Tubes required: 1—'22, 4—'12A. The New "Boss of the Air"—S-M 712 (Above)—A worthy successor to the famous Sar- gent-Rayment 710 of last season is the splendid new 712 tuner. Even if you have experienced the un- canny 10-kc. sharpness of the famous 5-vernier Sar- gent-Rayment—a new thrill comes with the 712. Here again are the five tuned circuits—two of them now joined in an ultra-modern band filter—and again the perfect shielding and the special shielded coils, whose tremendous accuracy makes possible the straight single dial tuning of the 712— without verniers, yet with performance far beyond competi- tion regardless of price. Feeds perfectly into any audio amplifier; the S-M 677 is ideal, furnishing also all necessary ABC power. Tubes required: 3—'24,1—'27. Price, only $64.90, less tubes, in shielding cabinet. Component parts total $40.90. Ideally suited for rack panel installations. Beautiful Cabinets The handsome new 707 table model shielding cabinet, fin- ished in rich crystalline brown and gold, suitable for 722, 735, or 735DC, is only $7.75. Special arrangements have been made whereby these receivers may be housed in magnificent consoles especially adapted to them. Be sure to send for the new Fall S-M General Parts Catalog, for details of these cabinets. S-M 233U Universal Output Transformer With a characteristic curve flat (to within 1.7 DB.) from 30 to 1OOOO cycles, this trans- former has the further advantage of extreme flexibility. Three windings, with a total of 12 lugs, enable it to be used to match almost any impedances. As an output transformer it will work out of '71, '45 or '50 tubes singly or in push-pull. It will work into 12 different impe- dances from 9 to 2OO ohms to feed directly into the voice coils of 1,2,3,4 or 8 dynamicspeak- ers. It will also match with 10OO, 2OOO, 4OOO or 8OOO ohm circuits; may be used as a line output transformer as well. Open mounted, size: 3' long, 3Ji' high, 3%' wide. Price, $9.OO. The RADIOBUILDER for October contains a full description of the 712 Tuner; 677 amplifier, and the new 233 Output Transformer, as well as an interesting article on Television Amplification. If you haven't seen it — use the coupon. If you build professionally—write us about the authorized S-M Service Station franchise —it paysl SILVER.MARSHALL, Inc. 6403 West 65th St., Chicago, U. S. A. F I 64 Silver-Marshall, Inc. *r 64O3 West 65th Street, Chicago, U. S. A. .... Please send me, free, the new Fall S-M Catalog; also sample copy of The Radiobuilder. For enclosed in stamps, send me the following: . SOc Next 12 issues of The Radiobuilder . *1.00 Next 25 issues of The Radiobuilder S-M DATA SHEETS as follows, at 2c each: .No. 3. 730. 731. 732 Short-Wave Sets .No. 4. 255, 256. etc., Audio Transformers .No. S. 720 Screen Grid Six Receiver . No. 6. 740 " Coast-to-Coast" Screen Grid Four .No. 7. 675ABC High-Voltage Power Supply .No. 8. 710 Sargent-Rayment Seven . No. 9. 678PD Phonograph-Radio Amplifier .No. 12. 669 Power Unit (for 720AC) .No. 14. 722 Band-Selector Seven .No. 15. 735 Round-the-World Six .No. 16. 712 Tuner (Development from the Sargent-Rayment) No. 17. 677 Power Amplifier for use with 712 I Name. I Address • N O V E M B E « 1929 • 59