Phonograph Monthly Review, Vol. 4, No. 12 (1930-09)

September, 1930, Vol* IV, No* 12 405 Columbia Model 991 Colu nibia “Tele-Focal” power detection is the underlying principle of the new Columbia models, a principle that guarantees ac- curacy, greater signal power, and establishes a uniform non- distorting sensitivity from one end of the dial to the other, and which enables the clear reception of distant stations on all wave-lengths through powerful locals, and without ampli- fying static. The “Tele-Focal” principle is particularly de- signed for the elimination of “dead spots”, so annoying in many areas. The new Columbia models offer also automatic volume control, accomplished with only one tube instead of the usual two, eliminating the necessity of having specially select- ed or matched tube-teams. To replace a tube, just another good tube is needed, not one that has to be factory selected. The radio set is an eight-tube screen-grid receiver, A.C., operated directly from house current, 100 to 130 volts, 60 cycles. There are four tuned circuits using three CX-324 tubes in the R. F. stages, and one CX-324 tube in the detec- tor—“Tele-Focal” power detection. There are two stages of Audio amplification, first stage resistance coupled using one C-327 tube, second stage in push-pull arrangement using two CX-345 tubes. There is an automatic volume control and tone level, long and short antenna control switch, self-per- petuating Mershon electrolytic condenser, phonograph pick- up terminals, free floating seven one-half inch diameter loud- speaker with special design fibre support at the center. Chas- sis and speaker are scientifically matched to produce perfect balance of tone, bass, and treble. The dial is illuminated and calibrated in kilocycles. In model C-20 the dimensions are 36 1/2 inches high, 28 inches wide, and 14 1/2 inches deep. The cabinet is a Low- boy adopted from early English. There is a sweep front case with instrument board and speaker opening framed by mold- ed top and bottom rails, and banked on each side with mold- ed pilasters. The center treatment of the pilasters shows linen fold with carved quarter-foil ornaments at each end. The cabinet is walnut finish. Price, less tubes, $145.00. Model C-21 is a High-boy cabinet influenced by the early Carolean period (an English period between the years 1660- 1688). There are carved pilasters leading up to the face of the case. The lines are accentuated by a dip in the apron and balanced by a carved frieze over the doors. The instru- ment board and speaker opening are reached through doors, the cabinet in open position retaining a finished and balanced appearance. A band-sawed straining rail gives motion to the entire case. Price, less tubes, $185.00. The instrument shown in the accompanying cut is Model 991, an automatic phonograph and radio combination, about which details will be available later. Victor Designed and constructed by a corps of radio engineers of the Radiola Division of the RCA Victor Company, the new Radiola Superheterodyne models have been created with im- provements which are considered outstanding in radio set build- ing, and which are capable of meeting all the requirements of the recption of modem broadcasting. The selectivitity of the new models is said to be three times that of any previous Radiola Superheterodyne model. Through the reserve power created by the screen grid Radiotron tubes, the listener is able to reach out and obtain the programs of distant stations with sharply defined and clear reception. The new models are encased in handsome cabinets of dur- able five-ply walnut veneer, carved with artistic decorative motifs, fitting them for the furnishings of any period. The con- struction has been designed to give the cabinets qualities of sturdiness, attractiveness, and good acoustical properties. The improved engineering features of the new models com- prise an improved electro-dynamic loudspeaker, to which the acoustics of the cabinet have been matched; the push-pull amplifier, making possible ample volume for any occasion and reduction of AC hum; the illuminated and magnified tuning dial, accurately calibrated in kilocycles for quick precise tuning; the volume control of new design, providing distortion-less control with maximum clarity; the local distance switch which in the local position permits the passage of a band of frequen- cies sufficiently wide to receive the utmost of broadcasts and in the distant position increases the sensitivity greatly at the same time that the band of frequencies admitted is narrowed down to enable clean separation of local from distant stations; and the improved filter design. Victor Model 86 Model 80 has a lowboy type of cabinet, 43 inches high, 27 inches wide, and 14 inches deep. Models 82 and 86 are of the console type; the former is 48 x 27^4 xl7 inches, and the latter 46 x 27 x 18 inches. Each model uses eight Radiotrons, four of which are the screen-grid type, used in radio frequency, first dectector and intermediate stages. Two UY-227’s are employed in the oscillator and thd power (second) dectector, and two UX-245’s are used in the push-pull power stage. There are nine tuned circuits, four of which are variable. In Model 82 there is the additional feature of the new tone color control, permitting the adjustment of tone to the listeners individual desire. Model 86, which also possesses the tone color control, is equipped with the latest type and improved electric phonograph, including an automatic stop, constant speed induction disc motor, and a new “inertia” pick-up which marks a decided improvement in the reproduction of records. The attractions and utility of home recording have prompt- ed the Victor company to develop a simple and inexpensive home recording device to be incorporated in the new Victor Radio-Electrola. A new and special type of microphone has been perfected for this purpose. The records will have two playing surfaces of six inches and will be inexpensive in cost. A simple and inexpensive home recording device has long been in demand, and the new Victor apparatus would seem well designed to fill this need. It will be available on the market sometime in September, and further details will be published as soon as they are available.