Audio Database


Pioneer C-90a
180,000yen(1988 release)

Control amplifier which supplied the technology and know-how of making the amplifier of Pioneer, and pierced through the design concept of the "simple is best."

The mono-construction structure which used the 3 transformer multi-power supply as the base is used for C-90a, and it made the power-source part on either side become independent for every transformer, is also separating the layout on the printed circuit board for every block, and has improved the separation.
Moreover, the circuitry of a video-system system and the power source of an electronic control system are supplied from power transformer with an another audio system, and a voltage stabilizer, and have prevented the cross interferencee.

The circuit board and a grounding substrate aim at a perfect separation, and the audio system and the video-system system are stopping the ill effect to a tone quality.

The hybrid MC transformer scheme by the combination of MC transformer which made the coil ratio the conventional one-half, and the equalizer amplifier which raised the gain of the decrement of a boost ratio is adopted as a Phono equalizer part. The part and bold-line material which make the coil ratio small can be used, and while making direct current resistance small, stray capacity between coils is also lessened. Thereby, the high region property is improving sharply.
Moreover, since gain of an equalizer amplifier can be lessened compared with a high gain equalizer amplifier, the total SN ratio can be raised.

The copper plating treatment of the whole chassis is carried out, and a magnetic distortion is reduced sharply.
Moreover, it is hard to generate an oscillation by join of a heterogeneous metals, and since the property to be hard to be influenced by oscillation is acquired, the vibration proof effect is also increasing.

The vibration proof part selected carefully by the sensitivity of a quantitive measurement and a technician was used, and the measures against vibration proof are taken thoroughly.
The plate mill of aluminum was adopted as the bonnet part, the extraneous vibration was stopped and the filling type large-sized insulator made from special cell polymer with a high vibration proof performance is adopted.
Moreover, under a transformer, the internal loss has adopted the copper plate which was greatly excellent in adhesion. A magnetic distortion is prevented while absorbing a fine oscillation.
The oscillation of the volume is prevented by absorbing a fine oscillation for attachment of the printed circuit board, a chassis, a transformer, etc., etc. using a copper plating screw, and also using the shaving appearance of aluminum Naked material with a large mass for a volume knob.

The relay and electronic switch which were examined more than enough are used for the change of a function etc., by switching by the nearness of an input terminal, leading about of a product line of a signal system was shortest-ized, and a loss and a failure of a signal are prevented.

While performing only an audio source, a function switch is interlocked with and the circuitry (PAT.P) which turns OFF the power source of a video-system system automatically is carried.

The non stress power cord which used the oxygen-free-high-conductivity-copper line with a polar window which had adopted the part for audios selected carefully by Hearing impression, and suppressed the influence of external noise,The volume which shielded during a vibration proof type film system capacitor, the closed mold relay for small signals which improved the robustness of the contact by suppressing an oscillation of a cap and preventing a break-in of sulfuration gas etc., and right and left with the non-magnetic material of the brass is adopted.
Moreover, the newly developed seal dead capacitor which connected the aluminum case with the cathode of the aluminum electrolytic capacitor more certainly is adopted, a capacitor element is shielded, and the diving of the noise from outside is stopped.

The S terminal of three inputs and three outputs is carried.
Moreover, sharpness, the detail, and the video-system enhancer that noise cancellation can control independently, respectively are built in (an enhancing functionality cannot be used in an S terminal).

Pioneer products and audio-video products of the other company including C-90a are controllable with an attached programmable remote controller unit with a learning function.

Rear Attached

Rating of a mode
Form Stereo control amplifier
<Amplifier part>
Input sensitivity/impedance Phono man month: 2.5mV / 50kohm
Phono MC: 250 microvolts/40 ohm
Phono MC: 125 microvolts/three ohm
compact disk, Tuner, Tape Play, Adaptor:150mV /, 50kohm
An Output voltage/impedance Tape Rec: 150mV / 1kohm
Pre out: 1V/600 ohm
Distortion (20Hz - 20kHz, 1V) Output:0.002%
Cross modulation distortion (50Hz:7kHz=4:1) Output:0.002%(1V)
Maximum output 8V (20Hz - 20kHz, 0.01%, 10kohm)
Frequency characteristic Phono man month: 20Hz-20kHz}0.2dB
Tuner and compact-disk:20Hz-20kHz+0 -0.1 dB
Tone control Bass: }9dB (100Hz)
Treble: }9dB (10kHz)
Filter Subsonic: 7Hz, 6dB / oct
High: 10kHz, 6dB / oct
Muting -20dB
SN ratio (A network)
Short circuit
Phono MM:96dB(5mV)
Phono MC: 86dB (500 microvolts)
Tuner, compact disk, Tape Play, VCR, Adaptor: 109dB
<Video-system part>
Input sensitivity/impedance VDP, VCR 1, 2, and 3, Adaptor, TV/Aux:1 Vp-p/75ohm
VCR 1 and 3, TV/Aux Luminance signal: 1 Vp-p/75ohm
Chrominance signal: 0.286 Vp-p/75ohm
An Output voltage/impedance VDP, VCR 1, 2, and 3, Adaptor, Rec Monitor, Monitor out: 1 Vp-p/75ohm
VCR 1 and 3, Monitor Luminance signal: 1 Vp-p/75ohm
Chrominance signal: 0.286 Vp-p/75ohm
DG 2%
DP 2 degrees
Frequency characteristic 10Hz-10MHz+0 -3 dB
Luminance-signal frequency characteristic 10Hz-10MHz+0 -1 dB
SN ratio 60dB or more
Luminance-signal SN ratio 60dB or more
Sharpness (2MHz) +6dB
Detail (0.5MHz) }3dB
Supply voltage AC100V, 50Hz/60Hz
AC outlet Power-switch interlock: One line, 500W
Power-switch un-interlocking.: Two lines, 500W (on/off with remote control is possible)
Power consumption
(Electrical Appliance and Material Control Law)
Dimensions Width 457x height 133x depth of 404mm
Weight 11.2kg
Adjunct Remote control CU-audio video005