YAMAHA CR-600
¥ 95,000 (around 1974)
Commentary
Stereo receiver using MOS FET.
A pure complimentary service OCL circuit directly connected to all stages is used for the main amplifier.
A well-regulated power transformer is used for the power supply section, and voltage is supplied from a constant voltage circuit to all circuits except the main amplifier section so that stable operation can be achieved without troubles caused by voltage fluctuations.
A transistor and a diode are used for the protection circuit. When a trouble occurs, a relay operates immediately to cut off the circuit.
This circuit also serves as power muting to prevent shock noise that occurs when the power switch is turned ON/OFF.
A monolithic IC is used in the equalizer amplifier section to achieve a high S/N ratio, low distortion factor and high stability characteristics.
A continuous loudness circuit is adopted for the loudness. By installing a special knob for adjusting the loudness, it is possible to correct the sense of hearing according to the actual listening environment.
In this circuit, if the volume is set to the normal listening position with the Loudness knob in the FLAT position, the volume can be controlled by simply turning the Loudness knob to increase the volume to a level 20 dB below the original volume while maintaining the optimum balance of audibility.
The tone control circuit is based on the Yamaha method in which NF is applied between the collector and emitter of the 2-stage direct-coupled amplifier.
This method has a low distortion rate and little residual noise, and provides flat characteristics without waviness at the middle point of the knob.
The FM front-end uses a dual-gate MOS FET with good high-frequency characteristics for the RF stage and mixer stage. It is combined with a precision four link varicon of linear frequency type to increase sensitivity and improve various interference rejection characteristics.
The IF stage consists of an IC and a four element ceramic filter, realizing linear phase characteristics and excellent limiter characteristics.
The MPX circuit uses a high-performance IC to minimize beat interference and interference from the SCA band. In addition, the MPX circuit is highly stable because the characteristics vary little depending on the input level.
An AFC circuit is mounted to maintain the optimum tuning point with maximum separation and minimum distortion.
The CR 600 is designed so that the AFC circuit is automatically turned off when the tuning knob is touched. Therefore, stations with weak radio waves can be accurately selected without being drawn into high-field stations.
In addition, the AFC/Station indicator lights faintly when you synchronize with the station during channel selection. When you release the knob, the indicator lights brightly to indicate that the AFC circuit is turned ON.
The tuning circuit of the AM tuner section is composed of a triple tuning system consisting of a triple air varicon, ceramic filter and two tuning coils to realize high stability and high selectivity. In addition, clear reception is possible even in high-electric-field regions by installing a dedicated AGC circuit for AM broadcasting, which has tended to increase power consumption.
An AGC is applied to the meter circuit, and the pointer swings linearly without saturation even at a strong input.
It has a built-in amplifier with three transistors for the microphone. In addition, microphone mixing is possible because the volume of the microphone is independent of the volume of other program sources.
Equipped with two tape circuits.
Equipped with low filter and high filter.
The preamp section and main amplifier section can be used separately.
Equipped with FM muting circuit.
Antenna terminals of 300 Ω balanced type and 75 Ω unbalanced type (with coaxial cable holder) are mounted.
Equipped with IF output terminal.
LED is used for the indicator on the dial face.
Model Rating
| Type | Stereo receiver | ||
| <Audio section> | |||
| Effective output (distortion factor 0.1%) |
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| Dynamic Power | 100W (IHF, 8 Ω) | ||
| Total harmonic distortion rate (20 Hz to 20 kHz) | 0.1% or Less (Effective Output) 0.04% or Less (at 1W output) |
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| Intermodulation distortion factor (70 hz : 7 khz = 4 : 1) | 0.1% or Less (Effective Output) 0.05% or Less (at 1W Output) |
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| Power Bandwidth (IHF, 0.5% distortion factor) | 5 Hz to 70 kHz | ||
| Frequency response (at 1W output) | Main in : 10 Hz to 100 kHz + 0 -1dB Phono (RIAA deviation) : 30 Hz to 15 kHz ± 0.5 dB Aux, Tape PB : 10 Hz to 50 kHz + 0.5 -1dB |
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| Damping factor | 70 (1 kHz, 8 Ω) | ||
| Load impedance | 4 Ω ~ 16 Ω | ||
| Input Sensitivity / Impedance (1 kHz, effective output) |
Phono1, 2 : 3mV/50k Ω Mic : 3mV/50k Ω Aux1, 2, Tape PB A, B : 150mV/45k Ω Main in : 775mV/50k Ω |
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| Maximum Allowable Input (1 kHz) | Phono : 135 mVrms (0.1% strain rate) Mic : 450 mVrms (Distortion Factor 0.3%) |
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| Output Level / Impedance (1 kHz) | Rec out A, B : 150mV/2k Ω Pre out : 775mV/2k Ω |
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| Tone control | Bass : ± 10 dB (50 Hz) Treble : ± 10 dB (10 kHz) |
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| Filter | Low:50Hz(12dB/oct) High:8kHz(6dB/oct) |
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| Loudness | Continuous loudness corresponding to an equal loudness curve | ||
| S/N (IHF, A Network) | Main in : 100 dB or more Phono : 75 dB or more Mic : 70 dB or more Aux, Tape PB : 90 dB or more |
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| FM Tuner Section | |||
| Receiving frequency | 76 MHz to 90 MHz | ||
| Practical Sensitivity (IHF, 84 MHz) | 2.0 μ V | ||
| Image interference ratio (84 MHz) | 90dB | ||
| IF Interference Ratio (84 MHz) | 95dB | ||
| Spurious interference ratio (84 MHz) | 95dB | ||
| AM suppression ratio | 55dB | ||
| Capture ratio | 1.5dB | ||
| Effective selectivity (IHF) | 75dB | ||
| S/N | 70dB | ||
| Total harmonic distortion rate (400 Hz) | mono:0.3% stereo:0.5% |
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| Stereo Separation (400 Hz) | 40dB | ||
| Frequency characteristic | 50 Hz to 10 kHz ± 1.0 dB | ||
| Subcarrier suppression ratio | 40dB | ||
| Muting signal level | 10 μ V | ||
| IF out level / impedance | 400mV/1k Ω | ||
| <AM Tuner Section> | |||
| Receiving frequency | 525 kHz to 1,605 kHz | ||
| Practical sensitivity (IHF, bar antenna) | 52dB/m | ||
| Selectivity (1000 kHz) | 30dB | ||
| <General> | |||
| Semiconductor used | IC : 4 Transistor : 59 MOS FET : 2 Diode : 33 pcs Zener diode : 3 pcs LED : 3 pcs |
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| Power consumption | 120W (rated) 200W maximum |
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| External dimensions | Width 474x Height 158x Depth 300 mm | ||
| Weight | 12.5kg | ||
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