Audio Database

The

Pioneer C-77
120,000yen(around the 1980 time)

Description
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The stereo preamplifier which improved the property of each circuitry and aimed at coexistence of multifunction nature and a tone quality.

The equalizer circuitry serves as circuitry of 3 steps of first rank differentials hardwired-connection Class-A SEPP by }2 power source.
The styrene capacitor of 2% of the error was combined with the precision nichrome vapor-deposition metals skin membrane resistance of 1% of the error, and the frequency characteristic of less than }0.2dB is secured to the NFB element in all the bands (20Hz - 20kHz).
In order to reproduce the dynamic range minced by the record, the high voltage of }48V is impressed to an equalizer circuitry.

Also when the cartridge from which an Output voltage differs is connected to two phone input terminals, the level control to a phone of -12dB (Input sensitivity of 2.5mV - 10mV) is possible for two so that level doubling may be made.
In a special 4-unit volume, the scheme with which -6dB controls the amount of NFB and -6dB to -12dB controls an Output voltage is adopted, when it extracts to -6dB or more, a maximum permissible input becomes large with about double 1V, and a using of a high-output cartridge is also possible.

The original twin tone control of Pioneer is adopted as a tone circuitry.
This circuitry is the scheme equipped with the control of 50Hz super-low-pass one and a 20kHz super-high region as a subcontrol besides a main control of Bass100Hz and Treble10kHz,Since a total of 5929 sorts of curves can be made combining a main and a factice, the advanced control united with the property is enabled.

By the decibel window of 22 contacts, the method of an attenuator with the precision of a window error of }0.2dB and a right-and-left interlock error of less than 0.2dB was made the volume, and it takes it.
Furthermore, the volume has adopted the special 4-unit type, in order to carry out an attenuate at two places, the preceding paragraph of control amplifier, and a subsequent stage, a noise decreases and its SN at the time of a using is usually improving.

Control functionalities, such as an attenuator of -15dB-30dB of 0dB, a high cut-off filter, two tapes duplicate switchpoints, and a tone switchpoint, are carried.

Internal

Rating of a mode
Form Stereo preamplifier
Circuit system Equalizer-amplifier part: 3 steps of first rank differentials hardwired-connection final-stage Class-A SEPP
Control amplifier part: 3 steps of first rank differentials hardwired-connection final-stage Class-A SEPP
Input terminal Phono1:2.5mV/50kohm
2:2.5 mV - 10mV of Phono / 50kohm
MIC: 2.5mV / 50kohm
Tuner, AUX1, 2:150mV / 100kohm
Tape Play1, 2:150mV / 100kohm
Phono maximum permissible input
(THD 0.05%, 1kHz)
Phono1:500mV
Phono2:500mV-1000mV
Output-terminal Tape Rec1, 2:150mV / 2.2kohm
Output(RL:50kohm): 2V/600 ohm, 7V/600 ohm
THD (20Hz - 20kHz) 0.03% (2V output)
0.05% (7V output)
Frequency characteristic Phono1, 2:20Hz-20kHz}0.2dB
Tuner, AUX, and TapePlay:10Hz-70kHz+0 -0.5 dB
SN ratio (IHF, A network)
Short circuit
Phono:74dB
Tuner, AUX, TapePlay: 90dB
Tone control
(1.5dB step)
Bass Main: }7.5dB (100Hz)
Sub: }4.5dB (50Hz)
Treble Main: }7.5dB (10kHz)
Sub: }4.5dB (20kHz)
Filter Low: 15Hz, 30Hz (12 dB/oct)
High: 12kHz, 8kHz (12 dB/oct)
Attenuator 0, -15, -30dB
The semiconductor used IC: Two pieces
Transistor: 50 pieces
Diode, other:31 piece
Supply voltage 100V, 50Hz/60Hz
Power consumption
(Electrical Appliance and Material Control Law)
17W
Dimensions Width 480x height 186.5x depth of 365mm
Weight 11.2kg
EIU specification rack mounting unit 4U