Radio Broadcast (May 1928-Apr 1929)

RADIO BROADCAST ADVERTISER 321 Nine Tubes (6 Screen Grid) •and What CAN'T They DO! The 1929 Laboratory "Super" THREE stages of screen grid radio-frequency amplification, a screen grid first detector, two stages of 65kc. intermediate screen grid I.F amplification, and a super-powered second detector — all copper shielded — working into an audio stage using the new Clough system — no wonder the 1929 Laboratory receiver spins rings around the best of superheterodynes! And all of this tremendous amplification, with selectivity that makes stations literally snap in and snap out, is controlled by two vernier drum dials, and a "volume" and a ''sensitivity" knob. No wonder it's easy to bring in stations from Maine to Florida, Texas, California, and Canada all in one evening. No wonder a log of a hundred stations can be piled up with this ultra-selective, extraordinarily sensitive screen-grid super that has out-performed every other superheterodyne tested against it! For the fan who wants real "super" results without squeals and station repeats clogging up his dials, the Laboratory Super is the set. Just imagine a super that can be tuned from one end of the. dials to the other right in Chicago without a single local station repeating, and yet be able to use a 65 kc. intermediate frequency with all the tremendous amplification this frequency, plus screen-grid tubes, gives. No wonder the new Laboratory Receiver is the set you've been looking for — a set so sensitive that you can out-demonstrate any other super with it at any time at all. And it has the ultra-fine tone that can be gotten only from the new S-M audio transformers and a stage of external light socket, push-pull 210 or 250 Unipac amplification, the highest powered, finest toned amplification that money can buy! If you've built lots of supers, and know what real results are, this set will give you a new thrill for distance, selectivity, tone. Despite its absolutely startling performance, the parts, mostly of S-M manufacture with all that this implies, cost but $95.20 complete, less Unipac amplifier which is not absolutely essential. And the overwhelmingly superior results the Laboratory Super will give, no matter what you compare it with, make it outstandingly the finest superheterodyne money can buy. Unipac Power Amplifiers Single Stage Unipac Amplifier Either of two S-M single stage power amplifiers replaces B batteries on any receiver and adds a stage of super-power amplification. Type 681210, the most powerful amplifier made for home use, employs 2-UX210 or UX250 power tubes in push-pull, two UX281 rectifiers, and a UX874 regulator tube. It supplies 45, 90, and 135 volts B to the radio receiver. A lower-powered unit is the 681-250, using only one UX210 or UX250 amplifier tube, but identical with the 681-210 in other respects. Price, 681-210 WIRED push-pull Unipac $102.00; or 681-210 KIT, $87.00. Both are ideal for the Laboratory super. Price 681-250 WIRED Unipac, $96.50; or 681-250 KIT, $81.50. Two Stage Unipac Amplifier Two complete two stage super-power Unipac Amplifiers, for amplification of radio set detector output or phonograph record pickup are the finest and most powerful of their types. S-M 682-210 uses one UX226 first stage tube, two UX210 or UX250 super-power tubes in a push-pull second stage, two UX281 rectifiers, and a UX874 regulator tube. It supplies two stages of power amplification and 45, 90, and 135 volts B power for a receiver, and A.C. filament power too. Type 681-250 is the same Unipac except that it uses only one UX210 or UX250 tube in the last stage. 682-210 WIRED push-pull Unipac lists at $117.00; or 682-210 KIT at $102.00. The 682-250 WIRED Unipac lists at $111.50; or 682-250 KIT at $96.50 ready to assemble. Fill Out the Coupon and Mail It to Us SETBUILDERS SUPPLY Romberg Bldg., Madison and Market Sts. CHICAGO Public Address Unipac 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 is the only lightsocket amplifier now available. It uses one UY227, one UX226, one UX250, and two UX281 rectifiers in three stages for microphone, radio, or record pick-up amplification. It is the ideal self-contained, portable or permanent amplifier for conventions, theatres, churches, etc. Prices : 685 WIRED Unipac, $160.00; or 685 KIT, ready to assemble, $125.00. We carry a complete line of S-M Parts and Kits, including all the big new headliners for immediate shipment; 720 Screen Grid Six Kit, $72.50; 720 Custom-Built Receiver, $102.00; 710 Sar gent-Ray ment Kit, $130.00; 740 Coast-toCoast Four Kit, $51.00; 730 Round-the-World Four Kit, $51.00; Complete Parts for 9-tube 1929 Laboratory Receiver $95.20. All can be shipped at once. Also the new Unipacs, power supplies, audio transformers, and other parts. Our new catalog will be a revelation to you — use the coupon and get it now! LIBERAL DISCOUNTS TO THE TRADE. CO. SETBUILDERS SUPPLY CO., Dept. 19-2 Romberg Bldg., Madison and Market Sts. Chicago, III. Send me at once, free, your new catalog listing S-M and other radio parts, cabinets, consoles, and accessories of highest quality. Name. Address ^Town State j