Radio Broadcast (May 1928-Apr 1929)

80 RADIO BROADCAST ADVERTISER Build and Own e Bosiloi the Air CP* K° "Without question the best receiving set of any type or description that we have ever demonstrated" — the above words of F. W. McDonell, a well-known New York radio engineer, typify the comments that stream in with the "station-on-every-channel" logs made with the record-demolishing S-M 710 Sargent-Rayment Seven. Using four of the most sensitive r.f. tubes made (screen-grid '22's) — five tuned circuits each with its own shielding and vernier knob — built with the complete S-M Clough audio system into an assembly where neither space, quality, nor cost has been spared — no wonder Japanese and Australian stations come in like locals on the west coast, and California stations are "regular stuff" to New York City dwellers. With such a kit, complete with beautiful aluminum cabinet, priced at only $130.00 ($175.00 wired) — there is but one wise course — get your order in now to your S-M Service Station or jobber! II 720 Screen Grid Six The new S-M 720 embodies in the most perfect form the revolution that screengrid tubes have brought about in longdistance reception. Three of these tubes in the R.F. stages, with shielded S-M coils, bring in distant stations on the next 10 kc. channel to powerful locals! The new S-M 255 and 256 transformers set a far higher standard of tone quality than ever known before. Custom-built complete in 700 cabinet, $102.00; complete fat, with pierced metal chassis and antique brass escutcheon but without cabinet, $72.50. 700 Shielding Cabinet Beautiful two-tone brown moire finish, with walnut finish wood base, $9.25. 740 Coast-to-Coast Four A time-tested and famous circuit — one R.F. stage, regenerative detector (nonradiating) and two A.F. stages — combined with immeasurably finer coils, the high efficiency of the screen-grid tube, all the gain of smooth-working regeneration, and new S-M Ciough-system audios, make the 740 the greatest value in the fifty-dollar class. WIRED in 700 cabinet: 740 (for D.C. tubes) $75; 740AC (A.C. tubes) $78. Kit less cabinet: 740, $51; 740 AC, $53. 685 Public Address Amplifier For coverage of crowds of 1,000 to 10,000 people, indoors or outdoors, with one to twelve loud-speakers, the 685 Public Address Unipac furnishes unequalled tonal clearness. WIRED $160.00; or KIT, $125.00. Other Unipacs $81.50 to $117.00. 730 Round-t heWorld Four The famous "Thrill Band" set — for long-distance broadcast reception; has S-M Clough-audio-system tone quality — splendid also for code. One screen-grid R.F. stage, regenerative (non-radiating) detector. Coils in kit tune from 17.4 to 204 meters; S-M 131X Coil ($1.25) extends range to 350 meters, and 13 1Y coil ($1.50) to 650 meters. Aluminum shielding cabinet included with 730 KIT $51, or fully WIRED $66. Also with 731 Adapter (plugs into ajiy receiver, converting it to short wave) KIT $36, WIRED $46. 732 Essential Kit, $16.50. B and ABC Power Supplies The 675ABC with an adapter allows a UX210 or UX250 power tube to be used in the last stage of any radio receiver — to which it supplies B power at 425, 135, 90, and 22 volts; also 22-90 variable. A and C power are supplied to the power tube, and IV2 and 2% volts for A.C. tubes if used. Uses one UX281 rectifier. Price $58 WIRED, or $54 in KIT form. 670ABC Power Supply has max. D voltage of 180; otherwise similar to the 675ABC. Price, WIRED, $46; KIT $43. 670B Power Supply for B power only, 180 volts max., and lower voltages as in 675ABC: WIRED $43.50; KIT $40.50. 676 Dynamic Speaker Amplifier A single-stage power amplifier, using one 250 type power tube and one 281 type rectifier. Used with any receiver, as a third stage before a dynamic speaker, it will give wonderfully improved volume and tone quality, WIRED, $55; KIT $49. Are you receiving "The Radiobuilder" regularly? Every issue describes new and interesting radio developments. To all Authorized S-M Service Stations, it comes free of charge; to others a nominal charge is made* Use this coupon. Silver-Marshall, Inc. 838 W . Jackson Blvd., Chicago, U. S. A. ....Please send me, free, the complete S-M Catalog; also sample copy of The Radiobuilder. For enclosed in stamps, send me the following : .... (50c) Next 12 issues of The Radiobuilder ($1.00) Next 25 issues of The Radiobuilder S-M DATA SHEETS as follows, at 2c each: No. 1. 670B, 670ABC Reservoir Power Units . . . .No. 2. 685 Public Address Unipac No. 3. 730, 731. 732 " Round-theWorld" Short Wave Sets No. 4. 223, 225, 226, 255, 256, 251 Audio Transformers . . . .No. 5. 720 Screen Grid Six Receiver . . . .No. 6. 740 "Coast-to-Coast" Screen Grid Four No. 7. 675ABC High-Voltage Power Supply and 676 Dynamic Speaker Amplifier .No. 8 Sargent-Rayment Seven No. 9 678PD Phonograph Amplifier If you build professionally, write us about the Service Station franchises. Or if you don't build, yet want your radio to be custom-made, S-M will gladly refer your inquiry to an Authorized Silver-Marshall Service Station near you. ■ jT ONE of our cooperating distributors, whose ^\ announcement directly follows, joins us in presenting a descriptive summary of some of the outstanding receiver and amplifier values to be found in the new S-M line. SILVERMARSHALL, Inc. 838 West Jackson Blvd., Chicago, U. S. A. 1_