Pioneer C-90a

Commentary

This is a control amplifier that uses Pioneer's amplifier manufacturing technology and know-how, and adheres to the design concept of "simple is best".

The C-90a employs a monoconstruction structure based on a 3-transformer multi-power supply. The left and right power supply sections are separated for each transformer, and the layout on the printed circuit board is separated for each block to improve the separation.
The power supply for the video circuit and the electronic control circuit is supplied from a power transformer and constant voltage circuit separate from the power supply for the audio circuit to prevent mutual interference.

The audio and video systems are completely separated from the circuit board and ground board to minimize adverse effects on sound quality.

The Phono equalizer uses a hybrid MC transformer system that combines an MC transformer with half the conventional winding ratio and an equalizer amplifier with an increased gain corresponding to the decrease in the step-up ratio. Because the winding ratio is reduced, thicker wire can be used, DC resistance is reduced and stray capacitance between windings is also reduced. This greatly improves the high-frequency characteristics.
In addition, the gain of the equalizer amplifier can be made smaller than that of the high-gain equalizer amplifier, so that the total SN ratio can be improved.

The entire chassis is plated with copper to greatly reduce magnetostriction.
In addition, the combination of dissimilar metals makes vibration less likely to occur and less likely to be affected by vibration. As a result, vibration isolation is also enhanced.

Using carefully selected anti-vibration parts based on quantitative measurement and the sensitivity of engineers, thorough anti-vibration measures are taken.
A thick aluminum plate is used for the hood to suppress external vibration, and a large filled insulator made of special cell polymer with high vibration damping performance is used.
In addition, a copper plate with high internal loss and excellent adhesion is used under the transformer to absorb microvibration and prevent magnetic distortion.
Copper plated screws are used for mounting printed circuit boards, chassis, transformers, etc. to absorb micro vibration, and the volume knob is machined out of massive solid aluminum to prevent volume vibration.

We use well-examined relays and electronic switches for function switching, etc. By switching near the input terminal, we minimize the routing of signal wiring and prevent signal loss and degradation.

It is equipped with a circuit (PAT. P) that automatically turns off the power of the video system in conjunction with the function switch when only the audio source is being played.

It uses audio parts carefully selected by hearing sense. It uses a non-stress power cord using a oxygen-free copper wire with a polarity display that suppresses the influence of external noise, a vibration-proof film capacitor, a small-signal sealed relay that increases the reliability of contacts by suppressing the vibration of the cap and preventing the entry of sulfurous gas, etc., and a volume that shields the left and right sides with a non-magnetic brass material.
In addition, we have adopted a newly developed sealed capacitor in which the cathode of the aluminum electrolytic capacitor and the aluminum case are connected more securely, shielding the capacitor elements and reducing noise from outside.

S jacks for input Route 3 and output Route 3 are mounted.
There is also a built-in video enhancer that can control sharpness, detail and noise cancellation independently (Enhanced function cannot be used with the S terminal).

The included programmable remote control unit with learning function controls Pioneer products including the C-90a and AV products of other companies.

Model Rating

Type	Stereo control amplifier
Amplifier Unit
Input Sensitivity / Impedance	Phono MM : 2.5mV/50k Ω Phono MC : 250 μ V/40 Ω Phono MC : 125 μ V/3 Ω CD, Tuner, Tape Play, Adaptor : 150mV/50k Ω
Output Level / Impedance	Tape Rec : 150mV/1k Ω Pre out : 1V/600 Ω
Distortion Factor (20 Hz to 20 kHz, 1 V)	Output:0.002%
Intermodulation distortion factor (50 hz : 7 khz = 4 : 1)	Output:0.002%(1V)
Maximum power output	8 V (20 Hz ~ 20 kHz, 0.01%, 10k Ω)
Frequency characteristic	Phono MM : 20 Hz to 20 kHz ± 0.2 dB Tuner, CD : 20 hz to 20 khz + 0 to 0.1 db
Tone control	Bass : ± 9 dB (100 Hz) Treble : ± 9 dB (10 kHz)
Filter	Subsonic : 7 Hz, 6dB/oct. High : 10 kHz, 6dB/oct.
Muting	-20dB
Signal-to-noise ratio (A network Short circuit)	Phono MM:96dB(5mV) Phono MC : 86 dB (500 μ V) Tuner, CD, Tape Play, VCR, Adaptor : 109 dB
<Video Part>
Input Sensitivity / Impedance	VDP, VCR1, 2, 3, Adaptor, TV/Aux : 1Vp-p/75 Ω VCR1, 3, TV/Aux Luminance Signal : 1Vp-p/75 Ω Color Signal : 0.286Vp-p/75 Ω
Output Level / Impedance	VDP, VCR1, 2, 3, Adaptor, Rec Monitor, Monitor out : 1Vp-p/75 Ω VCR1, 3, Monitor Luminance Signal : 1Vp-p/75 Ω Color Signal : 0.286Vp-p/75 Ω
DG	2%
DP	2 ゜
Frequency characteristic	10 Hz to 10 MHz + 0 -3dB
Luminance signal frequency characteristic	10 Hz to 10 MHz + 0 -1dB
Signal-to-noise ratio	60 dB or more
SN ratio of luminance signal	60 dB or more
Sharpness (2 MHz)	+6dB
Detail (0.5 mhz)	± 3 dB
<General>
Power supply voltage	100 VAC, 50Hz/60Hz
AC outlet	Power switch interlock : 1 system, 500W Power switch not linked : 2 systems, 500W (can be turned on/off by remote control)
Power consumption (Electrical Appliance and Material Control Law)	41W
External dimensions	Width 457x Height 133x Depth 404 mm
Weight	11.2kg
Attachment	Remote Controller CU-AV005