Radio Broadcast (May 1928-Apr 1929)

RADIO BROADCAST ADVERTISER 241 The Nine Tube Screen Grid laboratory tfeeeiwr/ Nine Tubes with Screen Grid Efficiency! THREE stages of screen grid radio-frequency amplification, a screen grid first detector, two stages of 65 kc. 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 under the control of 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 an evening. No wonder a log of a hundred stations can be piled up with this ultraselective, extraordinarily-sensitive screen-grid super that has outperformed 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, pushpull 210 or 250 Unipac amplification, the highest powered, finest toned amplification 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 that 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 681-210, the most powerful amplifier made, uses 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. Type 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 regular 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. 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 pickup amplification. It is the ideal self-contained, portable or permanent amplifier for conventions, theatres, churches, etc. Price 685 WIRED Unipac, $160.00; or 685 KIT, ready to assemble, $125.00. MEDIUM AND HIGH VOLTAGE POWER SUPPLIES B and ABC Power Units for Radio Sets S-M 670B Reservoir Power Unit has five different B voltages, of 22, 90, 135, and 180 volts fixed, and one variable voltage ranging from 22 to 90 volts. It will deliver up to 60 M.A. to operate any standard receiver, and is specifically recommended for S-M receivers. Type 670ABC is the same unit with Wi, 2\4 and 5 volt A.C. filament supply added, and is a complete ABC power plant for any A.C. tube equipped receiver. Both use one UX280 rectifier. Price, 670B, WIRED, $43.50 or in kit form $40.50. Price 670ABC power supply WIRED, $46.00, or, in kit form, $43.00. 675ABC High Voltage Power Unit Type 675 power unit is a high voltage power supply delivering 450 volts maximum. It is provided with an adapter which allows a UX210 or UX250 super-power tube to be used in the last stage of any receiver at all, to which the 675ABC supplies 22 fixed, 22 to 90 variable, and 90, 135, and 450 volts B power, as well as A and C power for the power tube, and 1J4 and 214, volts A.C. for A.C. tube filaments if used. It is the biggest power unit value ever offered, and costs but $58.00 WIRED, or $54.00 in kit form, less one UX281 ectifier tube* 676 Dynamic Speaker Amplifier This is a single stage power amplifier especially for use as a third stage, after any radio set, to boost volume and tone to give extra fine results with standard dynamic loud speakers. It uses one UX281 rectifier and one UX250 super-power amplifier, and has binding posts for receiver output connections, loud-speaker cord tips, and also for the dynamic speaker field. The 675 Amplifier operates any dynamic speakers having a 90 to 120 volt DC field, to which it supplies necessary power. Added to any set equipped with a dynamic speaker, it will provide a marvelous improvement in tone and volume. Price, 676 WIRED, $55.00; or 676 in KIT form, $49.00. We carry for your convenience a complete line of S-M Radio 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 Sargent-Rayment Kit, $120.00; 740 Coast-to-Coast Four Kit, $51.00; 730 Round-the-World Four Kit, $51.00; Complete Parts for 9-tube 1929 Laboratory Receiver $95.20. Any of these can be shipped at once, as uiell as the new XJnvpacs, 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. ' Setbuilders Supply Co. I Romberg Bldg., Madison &. Market Sts., Chicago, III. SETBUILDERS SUPPLY CO. ^ggigSg Chicago Send me at once, free, your new catalog listing S-M and other radio parts, cabinets, consoles, and accessories of highest quality. Name -j Address . I