971SRAL INFORHTI ON.
SR 51 has been especially designed to fill the nee'i for a high quality replacement or custom tuner of guch mechanical and circuit simplicity as to preclude the peg. sibility of unit obsolescence. Separate standari components are used throughout.

No special instructions for circuit ad jus tment are necessary. There are no trick circuits. To any technician skilled in AR - FM the allignment procedure is obvious.
090111 Ator parallel trimmer Adjustment rt 1500 KC. Serieg padder pt 800 KC.

INSTALLATION INSTRUCTIONS.
SR 51 control ghafts and escutcheon are designed for a face panel of not more than one quarter of an inch in thickness. Carefully check the unit with the proposed cabinet placement using the furnished paper template for cut-out marking.
The machine screws which now hold the bronze escutcheon to the transparent dial are for shipping convenience only and may be discarded. Bronze oval head wood screws are supplied to fasten the escutcheon to the cabinet panel.
The transparent control designation strip should be place over the control shafts and fastened into place after the tuner is in the cabinet to insure perfect placement.
Chassis mounting screws with retaining washers should not be so tight as to nullify the cushioning effect of the rubber feet.

CAUTION VENTILATION IS EXTREMELY IMPORTANT. in multi-tube unit should be housed in an insufficiently ventilated cabinet. Damage to the unit and the cabinet will result.

USE ONLY 1 1/2 AMP FUSE.

ANTENNA REQUIREMENTS.
For best non-directional standard AM broadcast result s & simple wire ten to twenty ft. in length connected to antenna terminal ANT will be sufficient. Additional selectivity to this efficient input circuit would tend to restrict the wide band reception capabilities of the detector

For best FM results a 100. M.C. dipole should be installed well above surrounding obstructions. The twisted 300 ohm line from the dipole should be connected to antenna terminals D1 and D2 (GND also grounds unit.)
A console type folded dipole is supplied with the tuner and will prove a satisfactory substitute in most cages where an external dipole is impractical.

INPUT JACKS.
All phono or TV audio signals as well as the AM and FM radio are subject to the volume and tone controls of the tuner unless DETECTOR output is used

The jack marked " AG " is the input for a properly compensated pre amplifier when using the variable reluctance cartridge.

CRYSTAL is the phono input for a standard crystal pickup.

The TV jack makes it possible to channel the audio of a television tuner thru the radio's amplifier and speaker

The OUTPUT jack should be connected to the high impedance input control (250,000 to 500,000 ohms) of a quality Audio amplifier. Use the prepared shielded lead supplied with the tuner. Choose a speaker capable of wide range reproduction,

A.C. POWER SR 51 is completely powerized for 110-125 volts 50-00 cycles. The power switch (on the Volume Control) also controls the A.C. receptacle on the back of the chassis for convenience in amplifier installation.

The A.M. Or Standard Broadcast section consists of a pre-stage tuned Radio Frequency section and one broad band stage of I.F. terminating in a new LOW DISTORTION detector for those who insist on the best in a Standard Broadcast Receiver. A'Null T " type in KC filter eliminates adjacent station whistle without impairing maximum frequency response.

The Frequency Modulation section employs a tuned R.F. stage preceded by an input coupling tube for added sensitivity and stability. An A.F.C. controlled Triode Oscillator, two stages of permeability tuned I.F. for superior F.M. performance and fully balanced static free Ratio Detector.

Input jacks are for phono pickups, either crystal pickup or properly compensated pre-amp for Variable Reluctance type pickup and a jack for aural television.

Two output jacks, one direct from detector for feeding a high quality recording amplifier, etc., the other allowing for full tuner control. A phono pre-amplifier power supply socket is provided for SR3 or similar unit.

SR 51 has the new SR tone-gate circuit for smooth electro-acoustical control of bass and treble emphasis allowing the controls of the audio amplifier to be pre-set. The newest in TWO TUBE tone control. Bass and treble variable from flat, minus is DB to plus is DB.

A.M. detector distortion only. 35 % at 400 cycles and. 8 % at 4000 cycles 100 % modulation.

10 K, C. filter attenuation zero at 9 K.C. and - 47 DB at in K.C.

F.M, Sensitivity: - 5 microvolts. Ratio Detector A.M. absorption 70 %

Tubes: Three 6BA6; two 6SN7GT and one each 6BE6; 6C4; 6J6; 6 AL5; 65A 7; 6SK 7; 6SF7; 6E5 and 5Y3.

Power Consumption:

85 watts, 110-125 volts, 50-60 cycles.