Pioneer QX-604
¥ 100,000 (released in 1973)
Commentary
A 4-channel receiver equipped with 3-format (CD-4/RM/SQ) 4-channel playback function.
With both RM and SQ matrix decoders and built-in demodulator for reproducing CD-4 discrete 4 ch, all 4 ch sources can be reproduced. In addition, 2 ch sources can be effectively reproduced by passing through the matrix decoder.
The CD-4 demodulator uses PLLs and FETs to give sufficient consideration to frequency characteristics and separation. It also incorporates an ASC circuit that automatically compensates for noise and improves S/N even for frequently used records.
The tone control uses a double volume, and both Bass and Treble can control the front and rear separately.
By using the balance control composed of 3 volumes, you can control the volume adjustment of front left and right, rear left and right, front and back.
The FM front-end is equipped with an FET, and the IF section is equipped with an IC and ceramic filter to improve the interference rejection capability. In addition, it is equipped with an on/off switching type FM muting to cut unnecessary long-distance stations.
4 ch CD-4, RM, SQ and 2 ch are displayed on the dial by switching the mode switch and lighting the lamp simultaneously.
Equipped with a loudness contour and headphone terminal.
Model Rating
| Type | 4-channel receiver | ||||||||
| FM Tuner Section | |||||||||
| Practical sensitivity (IHF) | 2.2 μ V | ||||||||
| Capture Ratio (IHF) | 3dB | ||||||||
| Effective selectivity (IHF) | 45 dB or more | ||||||||
| S/N | 65dB | ||||||||
| Image Interference Ratio (82 MHz) | 55 dB or more | ||||||||
| IF Interference Ratio (78 MHz) | 80 dB or more | ||||||||
| Spurious interference ratio (82 MHz) | 85 dB or more | ||||||||
| AM suppression ratio | 50dB | ||||||||
| Harmonic distortion factor | Mono : not more than 0.6% Stereo : 0.8% or less |
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| Stereo separation | 40 dB or More (1 kHz) | ||||||||
| Carrier leak suppression ratio | 35 dB or more | ||||||||
| Antenna | 300 ohm balanced 75 Ω Unbalanced Type |
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| Muting | ON/OFF enabled | ||||||||
| <AM Tuner Section> | |||||||||
| Practical sensitivity (IHF) | 15 μ V | ||||||||
| Selectivity | 25dB | ||||||||
| S/N | 50dB | ||||||||
| Image interference ratio | 45 dB or more | ||||||||
| IF interference ratio | 30 dB or more | ||||||||
| Antenna | Ferrite bar antenna | ||||||||
| Power Amplifier Unit | |||||||||
| Effective power |
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| Harmonic distortion factor | 1% or Less (Effective Output) | ||||||||
| Cross modulation distortion factor | 1% or Less (Effective Output) | ||||||||
| Output Bandwidth (IHF) | 4-Drive : 15 Hz ~ 20 kHz 2 ch drive : 10 Hz to 30 kHz |
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| Frequency characteristic | 10 Hz to 100 kHz ± 3 dB | ||||||||
| Damping factor (1 kHz, 8 Ω) | 40 | ||||||||
| Input Sensitivity / Impedance | Phono : 2.5mV/100k Ω Aux, Tape : 180mV/90k Ω |
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| Output Level / Impedance | Tape rec:180mV Tape rec(DIN):30mV Speaker : Front 1 set, Rear 2 sets Headset : 1 set for front |
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| Tone control | Bass : + 13 dB ~ -12.5 dB (100 Hz) Treble : + 11.5 dB ~ -8.5 dB (10 kHz) |
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| Loudness contour (at Volume -40dB) | + 10 dB (100 Hz), + 5 dB (10 kHz) | ||||||||
| S/N (IHF, short circuit A network) |
Phono : 70 dB or more Aux : 90 dB or more |
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| CD-4 Demodulator Part | |||||||||
| Input Sensitivity / Impedance | 2.5 mv (1 mv ~ 5 mv variable) / 100k Ω | ||||||||
| Distortion factor | 0.07% | ||||||||
| Separation (when standard signal 1 kHz is applied) | Left to Right : 50 dB Front to Rear : 30 dB |
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| Frequency characteristic | 20 Hz to 15 kHz | ||||||||
| <General> | |||||||||
| Power supply voltage | 100 VAC, 50Hz/60Hz | ||||||||
| Power consumption | 80W (rated) 160W maximum |
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| External dimensions | Width 525x Height 149x Depth 360 mm | ||||||||
| Weight | 12.3kg | ||||||||