What is stereo?




There are now two system of high fidelity, monophonic (monaural) and stereophonic. Monophonic is a system that starts from one microphone and is fed through a single high fidelity set. Stereophonic is a double system. Two separate microphones are placed at different sides of the orchestra and two different systems are used to keep the two signals or channels separated. Two separate speakers are used, placed on different sides of you room. Stereo is much like 3-D photography, two slightly different sound reach your ears giving you a new dimension in sound.




H.H. Scott '59





Akai AA-1125 receiver

Stereo Receiver AA-1125

Its ability to serve as an amplifier as well as a tuner, plus two tape monitor switches for monitoring independent tape decks or dubbing, make the AA-1125 perfectly versatile to fit your every audio need.

 


Outstanding Features

The differential pure complementary OCL circuitry with a plus/minus power supply is the reason for the AA-1125's better phase characteristics and excellent low range frequency directivity. It provides 25 watts per channel continuous power output, minimum RMS at 8 ohms from 40 to 20,000 Hz with no more than 0,5% Total Harmonic Distortion. And that's not all. The amplifier sections top grade, 3-stage, direct coupled negative feedback equalizer circuit extends phono input signal linearity to 110 mV (rms, 1 kHz) which assures a wide dynamic range and makes this not only a high quality receiver but top-notch amplifier as well. For FM broadcast listening, a stable FM stereo separation of more than 40 dB is possible due to a PLL (Phase Locked Loop) MPX section, and the IC equipped FM-IF section features a built-in quadrature detector that affords excellent linearity and minimal distortion over an exceptionally wide frequency range. In addition a 3-stage ceramic filter accounts for 70 dB FM selectivity. And the capture ratio is an amazing 1,3 dB. All these top quality circuits are located on one chassis board and the terminals have been directly soldered to the print board thus eliminating the regular mass of wires used in ordinary systems. This in turn eliminates signal loss and distortion pick-up due to wires and results in better tone quality.

 

Multiple Connections and Various Functions

The AA-1125 can be connected to numerous audio components including two full speaker systems. Dub from Tape 1 to Tape 2, connect a tape deck to Aux jacks and dub from Aux to tape 1 and Tape 2. simultaneous recording of a record or radio broadcast into two tape systems is possible. Controls include two tape monitor switches, a loudness switch for clearer low volume listening, a mode switch with FM muting circuit for quieter tuning, and push-button speaker switches for easier selection.

 

Elegant and Slim Styling

Designed to please your eyes as well as your ears, the AA-1125's new lighting system provides easy viewing of the linear dial scale and AM/FM tuning meter. In addition, the digital bass, treble, balance and volume controls facilitate easy adjustment. A slim receiver with tremendous versatility.

 


Specifications

Power Output:  25 watts per channel (min. RMS, at 8 , 40 - 20,000 Hz , with no more than 0,3% T.H.D.)

Power Bandwidth (IHF):  15 Hz to 40 kHz (T.H.D. 0,3% at 8 )

Signal-to-Noise Ratio (IHF):

Phono :  better than 75 dB at 8

Aux :  better than 90 dB

Residual Noise:  less than 0,8 mV at 8

Channel Separation (IHF):

Phono :  better than 50 dB at 1 kHz

Damping Factor:  more than 30 (1 kHz, 8 )

Output:

Speakers :  A, B (4 to 16 ); A + B (8 to 16 )

Headphones :  4 to 16

Input Sensitivity/Impedance:

Phono :  3 mV/47 k

Aux :  150 mV/100 k

Tape Monitor 1 :

Input [PIN / DIN} :  150 mV/100 k   / 150 mV/100 k

Output [PIN / DIN} :  150 mv/100 k   / 30 mv/180 k

Tape Monitor 2 :

Input [PIN} :  150 mV/100 k

Output [PIN} :  150 mv/100 k

Frequency Response:

Phono (RIAA) :  30 Hz to 15 kHz ±1 dB

Aux, Tape, Monitor :  10 Hz to 70 kHz +0 -2 dB

Tone Control:

Bass :  ±9 dB at 100 Hz

Treble :  ±9 dB at 10 kHz

Loudness Control:  +10 dB at  100 Hz; +5 dB at 10 kHz (volume control set at -30 dB)

FM Tuner Section

Frequency Range:  88 MHz to 108 MHz

Sensitivity(IHF):  1,9 µV

Capture Ratio:  1,3 dB

Selectivity (IHF):  more than 70 dB

Image Rejection:  more than 65 dB (at 98 MHz)

IF Rejection:  more than 90 dB (at 98 MHz)

Spurious Rejection:  more than 90 dB (at 98 MHz)

AM Suppression:  50 dB

Signal-to-Noise Ratio:  65 dB

T.H.D.

Mono :  less than 0,3% (100% mod)

Stereo :  less than 0,6% (100% mod)

Stereo Separation:  more than 40 dB at 1 kHz

Subcarrier Suppression:  more than 52 dB

AM Tuner Section

Frequency Range:  520 kHz to 1605 kHz

Sensitivity (IHF):

Bar Antenna :  180 µV/m

External Antenna ;  10 µV

Selectivity (IHF):  more than 30 dB

Image Rejection:  more than 65 dB at 1 kHz

IF rejection:  more than 45 dB

Signal-to-Noise Ratio:  more than 45 dB

Tuning Indicator Meter:  FM Center Tuning/ AM Signal Strength Meter

Muting Level Control:  On (stereo)/Off (monaural) Switch

Antenna Input Impedance:  300   (balanced); 75   (unbalanced)

Miscellaneous

Semiconductors:  27 Transistors; 12 Diodes; 1 FET; 4 ICs

Power Requirement:  110/220/240 V switchable, 50/60 Hz

Dimensions (W x H x D):  480 x 128 x 268 mm (18,9" x 4,8" x 10,6")

Weight:  6,8 kg (15,0 lbs)

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