Pioneer C-77
¥ 120,000 (around 1980)
Commentary
A stereo preamplifier that improves the characteristics of each circuit and achieves both multifunctionality and sound quality.
The equalizer circuit is composed of a first stage differential 3-stage directly connected class A SEPP with ± 2 power supply.
The NFB element combines a precision nichrome evaporated metal film resistor with an error of 1% and a styrofoam capacitor with an error of 2% to ensure frequency characteristics within ± 0.2 dB over the entire 20 Hz-20 kHz band.
A high voltage of ± 48 v is applied to the equalizer circuit in order to reproduce the dynamic range recorded on the record.
When cartridges with different output voltages are connected to the two phono input terminals, the level of the phono 2 can be controlled up to -12dB (input sensitivity 2.5 mV ~ 10 mV) so that the level can be adjusted.
It is a special 4-connected volume, and uses a method of controlling the NFB quantity up to -6dB and the output level from -6dB to -12dB. When it is limited to -6dB or more, the maximum allowable input becomes about twice as large as 1 V, and high output cartridge can be used.
The tone circuit uses Pioneer's original twin-tone control.
In addition to the main control of Bass100Hz and Treble10kHz, this circuit is equipped with sub control of 50 Hz ultra-low frequency and 20 kHz ultra-high frequency. A total of 5929 curves can be generated by combining the main and sub, enabling advanced control according to characteristics.
The volume is measured in 22-contact decibels with a display error of ± 0.2 dB and a left-right linkage error of 0.2 dB. The attenuator is used for the volume.
In addition, the volume is a special 4-channel type, and it is attenuated at two points, the front and back of the control amplifier, so noise is reduced and SN in normal use is improved.
It is equipped with control functions such as 0 db, -15dB and -30dB attenuators, high-cut filter, two series of tape duplicate switches and tone switches.
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Model Rating
| Type | Stereo preamplifier | ||||
| Circuit system | Equalizer amplifier : first stage differential 3-stage direct connection, last stage A-class SEPP Control amplifier section : first stage differential 3-stage direct connection final stage A class SEPP |
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| Input terminal | Phono1 : 2.5mV/50k Ω Phono2 : 2.5 mV to 10mV/50k Ω MIC : 2.5mV/50k Ω Tuner, AUX1, 2 : 150mV/100k Ω Tape Play1, 2 : 150mV/100k Ω |
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| Phono maximum allowable input (Harmonic distortion rate 0.05%, 1 kHz) |
Phono1:500mV Phono2 : 500 mV to 1000 mV |
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| Output terminal | Tape Rec1, 2 : 150mV/2.2k Ω Output (RL : 50k Ω) : 2V/600 Ω, 7V/600 Ω |
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| Harmonic distortion factor (20 Hz to 20 kHz) | 0.03% (2 v Output) 0.05% (7 v Output) |
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| Frequency characteristic | Phono1, 2 : 20 Hz to 20 kHz ± 0.2 dB Tuner, AUX, TapePlay : 10 hz to 70 khz + 0 to 0.5 db |
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| Signal-to-noise ratio (IHF, A-network Short circuit) |
Phono:74dB Tuner, AUX, TapePlay : 90 dB |
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| Tone control (1.5 dB step) |
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| Filter | Low : 15 Hz, 30 Hz (12dB/oct.) High : 12 kHz, 8 kHz (12dB/oct.) |
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| Attenuator | 0, -15, -30dB | ||||
| Semiconductor used | IC : 2 Transistor : 50 Diode, Other : 31 |
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| Power supply voltage | 100 V, 50Hz/60Hz | ||||
| Power consumption (Electrical Appliance and Material Control Law) | 17W | ||||
| External dimensions | Width 480x Height 186.5x Depth 365 mm | ||||
| Weight | 11.2kg | ||||
| EIU standard rack mounting unit | 4U |