Pioneer C-90

Commentary

This stereo control amplifier was developed as the culmination of a review of the amplifier from its starting point.
Based on the design philosophy of "Simple is best", the technologies developed by Pioneer are generously invested.

It is a twin monoconstruction structure based on 3 transformer multi-power supply.
The power supply for the L/R has been made independent of each transformer, and the layout on the printed circuit board has been separated into blocks to eliminate the unstable orientation caused by the deterioration of separation.
In addition, the power supply for the video circuit and electronic control system is supplied from a power transformer and constant voltage circuit separate from the power supply for the audio system.

The video circuit is equipped with a new circuit (PAT. P) that automatically turns off the power of the video circuit in conjunction with the function switch when the audio source is played back.

Various anti-vibration parts are used to cancel out vibration.
Polycarbonate is used for the insulator, which has a large internal loss and efficiently absorbs vibrations.
In addition, the circuit board is fixed with rubber vibration isolators, and the rubber vibration isolators that connect the board and chassis serve as dampers to prevent vibration from being transmitted to parts.
A copper plate with high internal loss and excellent adhesion is laid at the bottom of the transformer to absorb microvibration and prevent magnetic distortion.
In addition, copper plated screws are used for mounting printed circuit boards, chassis, transformers, etc. to absorb microvibration and prevent magnetic distortion.
Solid aluminum with a mass of 110g is used for the volume knob.

Carefully selected relays and electronic switches are used to switch functions, greatly reducing the wiring from the CFC to the panel and preventing signal loss and deterioration.

It employs a hybrid MC transformer system that combines an MC transformer with half the conventional winding ratio and an equalizer amplifier with a higher gain for the reduced boost ratio.
Since a thicker wire can be used because of the smaller winding ratio, the DC resistance is reduced and the stray capacitance between the windings is also reduced, and the high-frequency characteristics are greatly improved.

The entire chassis is plated with copper to greatly reduce magnetostriction.
In addition, since dissimilar metals (hard and soft metals) are integrated, it is less susceptible to vibration and more susceptible to vibration.

The volume does not use an electronic system, but uses a system in which a mechanical high-grade volume is driven by a motor. This motor is a clutch type, and the motor separates when manual operation is performed, so you can enjoy comfortable operation feeling.

The video section contains a full-fledged video enhancer that controls sharpness, detail, and noise cancellation independently.
In addition, it is equipped with a Rec Monitor Out, which enables recording while monitoring the enhancement effect during recording.

Model Rating

Type	Stereo control amplifier
Input Sensitivity / Impedance	Phono MM : 2.5mV/50k Ω Phono MC/40 Ω : 250 μ V/40 Ω Phono MC/3 Ω : 125 μ V/3 Ω CD, Tuner, Tape Play1, 2, VDP, VTR1, 2, 3, TV Tuner : 150mV/50k Ω
Output Level / Impedance	Tape Rec : 150mV/1k Ω Pre Out : 1V/600 Ω
Phono maximum allowable input (1 kHz, 0.1% distortion rate)	Phono MM:200mV Phono MC/40 Ω : 20 mV Phono MC/3 Ω : 10 mV
Tone control	Bass : ± 9 dB (100 Hz) Treble : ± 9 dB (10 kHz)
Signal-to-noise ratio (IHF, short circuit A network)	Phono MM:96dB(5mV) Phono MC : 86 dB (500 μ V) Tuner, CD, Tape Play, VDP, VTR : 109 dB
Power supply voltage	100 VAC, 50Hz/60Hz
Power consumption (Electrical Appliance and Material Control Law)	36W
External dimensions	Width 457x Height 124x Depth 404 mm
Weight	9.7kg
Attachment	Remote Controller CU-C001