Audio Database

Image of the C-70
Commentary

An AV control amplifier equipped with direct construction II and clean ground system.

Direct Construction II is used to minimize the signal path.
To minimize the path, we use relays and electronic switches that take sound quality into consideration, and place the input selector switch and REC selector switch at the shortest position immediately after the signal input section.
In addition, the volume is assembled on the same plane as the circuit board by placing it very close to the selector switch, and the distance from the circuit section to the signal output is also minimized. Especially in the direct on mode, the distance from the input to the output is shortened to 50 cm by combining with the proper position of each circuit block.

To prevent harmful noise current from adversely affecting the signal path, Pioneer's original clean ground system is installed.
The contact points between the circuit and the chassis are thoroughly reviewed and the power transformer and chassis, which are sources of noise, are insulated to prevent noise from entering the signal path.
In addition, the connection between the circuit and the chassis is connected at an appropriate point after considering the wiring, and a bypass path is provided to return only the noise current to the noise source.

In order to prevent the signals of each block from transmitting through the power supply and interfering with other circuits due to their individual characteristics, we have adopted a luxurious two transformer multi-supply power supply configuration in which the audio system, control system and video system are converted into separate transformers.
The power supply for the control system, which tends to generate pulsed noise, and the power supply for the video system, which is responsible for amplification of broadband frequencies including the audio band, are made independent of the power supply for the audio system to completely eliminate interference.

The video circuit board is housed in a metal case as a shielding measure in order to prevent interference with the audio circuit by amplifying the wide-band signal even outside the power supply part. Interference is suppressed by a completely separate design arranged to suppress interference even at the distance and position from the audio and video circuit boards to the ground line.
In addition, it is equipped with a local power off function that automatically turns off the power of video circuits that do not operate during audio playback, video circuits that do not operate except during record playback, and phono equalizer circuits that are not used except during record playback.
In addition, we have adopted a silent operation microcomputer that stops oscillation when no operation is performed for the control microcomputer of the switches. This eliminates as much as possible the cause of sound quality degradation and greatly improves the S/N feeling in actual operation.

We use carefully selected parts with particular attention to sound quality.
High-precision control and S/N in actual use are greatly improved for the volume, and newly developed motor-driven 4-series volume that realizes smooth movement is adopted.
We also thoroughly examine the materials, characteristics, and sound quality of low-noise operational amplifier ICs, capacitors, resistors, substrates, and lead wires.

Audio Line 5 and video Line 5 input jacks are installed.
Gold plated terminals are used for all input / output terminals, and S terminal is also used for image terminals.

You can also use a REC selector, a BGV function to play a CD sound on the video image, and recording on the back.

It is equipped with a fixed output to support surround processors.
This jack is output at a constant level so that the processor can control the level of each channel and master. It is also compatible with a power amplifier equipped with volume.
The output is through when the direct is turned on, and the signal that has passed the balance volume and subsonic filter is output when it is turned off. The output is adjusted according to the output level of the source and the setup time.

It comes with a remote controller with a learning function that can store the commands of other remote controllers and summarize their operations.
Most of the equipment can be controlled by this remote control, and the color coding and arrangement of operation switches have also been examined to improve usability.
Equipment with Pioneer SR mark can be controlled as it is.

Model Rating
Type AV control amplifier
Amplifier Unit
Input Sensitivity / Impedance Phono MM : 2.5mV/50k Ω
Phono MC : 0.25mV/100 Ω
CD, Tuner, Tape Play, LD, TV/AUX, Video, VCR Play : 150mV/50k Ω
Output Level / Impedance Tape Rec, VCR Rec, Tape2Monitor Rec : 150mV/2.2k Ω
Pre Out Variable : 1V/1k Ω
Fixed : 150mV/2.2k Ω
Total harmonic distortion factor
(20 Hz to 20 kHz)
Pre Out Variable : 0.002% (1V/10k Ω)
Fixed : 0.001% (150mV/50k Ω)
Maximum power output Pre Out Variable : 7V/10k Ω (20 Hz to 20 kHz, 0.01%)
Frequency characteristic Phono MM : 20 Hz to 20 kHz ± 0.2 dB
Phono MC : 20 Hz to 20 kHz ± 0.3 dB
CD, Tuner, Tape Play, LD, TV/Aux, Video, VCR Play : 1 hz to 150 khz + 0 to 3 db
Tone control
(Volume-40dB)
Bass : + / - 8 dB, 100 Hz
Treble : ± 8 dB, 10 kHz
Filter Subsonic : 17 Hz, -12dB/oct.
Muting - ∞ dB
Signal-to-noise ratio (IHF, A-network
Short circuit)
Phono MM:93dB(5mV)
Phono MC : 76 dB (500 μ V)
CD, Tuner, Tape Play, LD, TV/AUX, VIdeo, VCR plaY : 106 dB
<Video Part>
(Composite)
Input Sensitivity / Impedance LD, TV/AUX, Video, VCR1, 2 : 1Vp-p/75 Ω, Unbalanced
Output Level / Impedance VCR1, 2, Monitor : monitor : 1Vp-p/75 Ω, Unbalanced
DG Not more than 2%
DP 2 degrees or less
Frequency characteristic 10 Hz to 10 MHz + 0 -3dB
Signal-to-noise ratio 60 dB or more
(S terminal part)
Input Sensitivity / Impedance LD, TV/AUX, Video, VCR1, 2
Luminance signal : 1Vp-p/75 Ω, Unbalanced
Color Signal : 0.286Vp-p/75 Ω, Unbalanced
Output Level / Impedance VCR1, 2, Monitor
Luminance signal : 1Vp-p/75 Ω, Unbalanced
Color Signal : 0.286Vp-p/75 Ω, Unbalanced
Luminance signal frequency characteristic 10 Hz to 10 MHz + 0 -3dB
SN ratio of luminance signal 60 dB or more
<General>
Power supply voltage 100 VAC, 50Hz/60Hz
Power consumption 300W (Electrical Appliance and Material Control Law)
AC outlet Power switch interlock : 2 systems, 400W
Power switch not linked : 1 system, 100W
External dimensions Width 420x Height 163x Depth 417 mm
Weight 10.6 kg or less
Attachment Remote Controller CU-C004