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

Technics SU-7300 (1978)

Constructed by technical standards usually reserved for sophisticated separate pre-amplifier and power amplifier units, the SU-7300 provides superb performance at a very reasonable cost. The excellent specifications only suggest the pure, natural, transparent sound this unit is capable of, when combined with components of equal caliber. Not to be overlooked are its elegant, brushed aluminum front and luxurius cabinet styling, which give it an appearance to match the beauty of its sound.

Current Mirror Loading Attains Extremely High S/N Ratio in Equalizer and Low Distortion in Power Circuits
A classic dilemma in amplifier circuitry is that higher operating current (for gain), produces a correspondingly higher level of noise. To solve this problem, Technics employs current-mirror loading in the differential amplifier first stages of the equalizer circuit and the power amplifier. The results are a higher S/N ratio in the equalizer and lower distortion in the power stage.

78 dB S/N Ratio (IHF) at 2,5 mV Phono Input Sensitivity.
The 78 dB signal-to-noise ratio is the eqivalent of a 1/8,000th noise component in the music signal. In real terms, this means that noise won't interfere with your enjoyment of music, even during very soft musical passages. This extreme "quietness" of the phono equalizer is another result of advanced current mirror circuit design.

RIAA Compensation Accurate Within ±0,3 dB.
The playback equalization characteristics of the SU-7300varies by only ±0,3 dB from the RIAA recording characteristic for phonograph records. It will produce no perceptible coloration of sound.

0,08% THD (20 Hz -20 kHz) at Rated Output
Amplifier power is useful only if it is delivered free of distortion. At any powerlevel, from a whispering 250 mW to the full roar of 41 watts per channel, the total harmonic distortion of the SU-7300 is an imperceptible 0,08%. The impressive distortion rating also applies to the low power output of 250 milliwatts. Use of the matched transistor pairs in a single package and the already mentioned current-mirror loading contribute to the low distortion.

Two-Way Dubbing
The tape selector circuit permits two tape decks to be connected at the same time  to the SU-7300. dubbing may be performed between the two decks in either direction.
Additionally, as the tape monitor and recording mode switches operate independently, you can use the SU-7300 to listen to a record or FM program source while tape dubbing is in progress.

41-Step Volume Control
To provide precise, repeatable volume settings, the volume control has 41 click-stops.

High Filter
Cuts down high frequency noise such  as record scratches and tape hiss. Cut-off slope is -6 dB at 8 kHz.

Direct Reading Power Meters
The large scale meters provide direct readout (at 8 Ω) of amplifier output power in watts, with instantaneous tracing of signal peaks. To improve linearity at low output, a germanium diode is uded for rectification. Two ranges are provided (x1 and x0,1) for accurate monitoring of all output levels.

Loudness Switch
Use of this feature boosts the lower and upper ranges of the audio signal to compensate for the poor response of the humen ear to extremes of frequency at low levels. It is useful when listening to music late at night, when the volume setting is very low.

Main, remote Speaker Connections
Two pairs of speakers may be connected. A pushbutton selector permits selection of either pair.

Amplifier Section
Continuous Power (1 kHz):55 W + 55 W at 4 Ω (both channel driven); 43 W + 43 W at 8 Ω
Power Continuous (20 Hz - 20 kHz): 48 W + 48 W at 4 Ω (both channel driven); 41 W + 41 W at 8 Ω
Power Bandwidth: 8 Hz ~ 55 kHz , -3 dB (both channel driven at 8 Ω)
Total Harmonic Distortion:
0,08% at rated power (20 Hz - 20 kHz);
0,04% at half power (20 Hz - 20 kHz);
0,02% at half power (1 kHz)
Intermodulation distortion: 0,08% (60 Hz : 7 kHz = 4 : 1, SMPTE)
Residual Hum and Noise: 0,6 mV
Damping factor: 20 (4 Ω), 40 (8 Ω)
Input Sensitivity and Impedance:
Phono: 2,5 mV/47 kΩ
Tuner: 150 mV/47 kΩ
Tape1 Playback: 180 mV/47 kΩ
Tape2 Playback: 150 mV/47 kΩ
Tape1 Rec/Play: 180 mV/47 kΩ
Phono Max. Input Voltage: 150 mV (1 kHz, RMS)
Signal-to-Noise Ratio (IHF, A):
Phono: 78 dB
Tuner: 97 dB
Frequency Response:
Phono: ±0,3 dB, RIAA standard curve
Tuner: 7 Hz - 80 kHz, +0 dB, -3 dB; 20 Hz - 20 kHz, ±0,5 dB
Tone Controls:
Bass: +12 dB, -12 dB (50 Hz)
Treble: +12 dB, -12 dB (20 kHz)
High Filter: 8 kHz, -6 dB/oct
Loudness control (volume at -30 dB): 100 Hz, +8 dB
Output Voltage and Impedance:
Rec Out (Tape 1, 2): 150 mV/1,2 kΩ
Rec/Play (Tape 1) output: 30 mV/82 kΩ
Load Impedance: Main or Remote: 4 - 16 Ω
Power Consumption: 400 W
Power Supply: 110/120/220/240 V, 50/60 Hz
Dimensions (W x H x D): 410 x 139 x 334 mm (16-5/32" x 5-15/32" x 13-5/32")
Weight: 8,9 kg

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