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RADIO BROADCAST
No. 28
Radio Broadcast's Set Data Sheets
THE SONORA MODEL A-36 RECEIVER
July, 1929
This receiver consists of four stages of tuned r.f. amplification, a grid leak and condenser detector, and a two-stage transformercoupled audio-frequency amplifier. The set contains the following interesting features: combined electromagnetic and electrostatic
AVERAGE VACUUM TUBE AND LINE VOLTAGES FOR SONORA INSTRUMENTS Models A-20;A-36;A-44;A-46
coupling in the r.f. amplifier, a special first-stage a.f. transformer phonograph pick-up, a push-pull output stage, an electrodynamic loud speaker, and an automatic control to compensate variations in line voltage.
Line Voltages
125
120
115
110
105
Primary Voltages across Transformer
87
84
82
50
77
Radio Amplifier Tubes Type RA-1
Filament Voltage
16.0
15.6
15.2
14.8
14.4
Plate Voltage
125
122
118
115
112
Plate Current mA.
5.4
5.2
5.0
4.9
4.7
Grid Bias Voltage
4-6
.4-6
4-6
4-6
4-6
Detector Tube Type DE-1
Filament Voltage
2.4
2.3
2.2
2.1
2.0
Plate Voltage
22
21
20
19.5
19
First Audio Amplifier Tube Type DE-1
Filament Voltage
2.4
2.3.
2.2
2.1
2.0
Plate Voltage
115
112
110
107
104
Plate Current mA.
6.0
5.8
5.6
5.3
5.1
Grid Bias Voltage
'6.5
6.2
5.9
5.6
5.3
Push-Pull Audio Amplifier Tubes Type SO-2
Filament Voltage
7.9
7.7
7.5
7.3
7.0
Plate Voltage
435
420
405
390
380
Plate Current mA.
47
45
43
41
39
Grid Bias Voltage
87
84
80
77
73
Brown-green
Gnd.VAnt
Yellow-blackYellow
Red-black Green Brown' 'Brown-black •-Maroon-black
FREED-EISEMAN RECEIVER MODEL NR-78 A.C.
The nr-78 is a completely a.c.-operated receiver using five heater tubes, two power tubes arranged in push-pull, and a full-wave rectifier. Unlike many other sets, the antenna stage in this receiver is tuned by means of a variometer in conjunction with a variable
condenser. Either a long or short antenna may be used. The set also contains a 1-mfd. condenser connected to one side of the power circuit so that the light socket may be used for the antenna by simr. ly connecting together two binding posts.
4= 0.00025
Line Switch
160 •
• JULY .1 929 •