Audio Database

The

Pioneer A-838
120,000yen(October, 1989 release)

Description
 
The Integrated Amplifier which supplied the new technology of a clean grand system etc. in addition to no vibrating and an absent-resonance-ized design.

In order to shut out the harmful noise electric current generated in a power-source part or a large-current part from an electrical circuit, the clean grand system is adopted.
It insulated from the chassis, the power transformer and heat sink used as the source of the noise were attached, and it has prevented a noise flowing into a signal path. Furthermore, by preparing the it1 which carries out connection of the contact of a circuitry and a chassis to a suitable point, and returns a noise electric current to a noise source, it is considered so that a noise may not mix in the signal current.

In order to shorten a signal path and to prevent a failure and interference of a signal, direct construction IBM PCN II is adopted. Inheriting the technology of the conventional direct construction, the power amplifier board and the main volume substrate were unified, and while reducing a product-line numbers of steps sharply, the signal path length of 85cm is realized.
In input block, it is considered as the structure which operates an input selector and a main volume by remote control mechanically, and shortest-ization of the signal path is attained.
Furthermore, an input signal does not flow into the front panel side at all by turning ON a Source-Direct switchpoint, but a purer sound can be enjoyed.
The power amplifier block is arranged along with the fluence of a signal, and leads the output of the stage of power to a speaker block straight. Moreover, distance from a power-source part is shortest-ized.
In the speaker block, direct installment and shortest-ization is attained for the speaker termination to the substrate which attached the relay.

Power is directed towards the elucidation of an oscillating propagation mechanism for no vibrating and the measure against absent-resonance-ized, making full use of the modal analysis by a computer,The double-sided vinyl chloride steel plate which improved the periodic-damping property to the structure quality of the material of a shielding case, or a bottom plate and a bonnet case further based on the result is used.
Moreover, a single-sided vinyl chloride steel plate is adopted as chassis, such as a rear panel, panel stay, and a transformer frame, and absent-resonance-ization of the part is attained.
The honeycomb by a press stops is adopted as frame chassis, in order to suppress an oscillation and vibration of a power transistor to a heat sink, the filling type large-sized honeycomb insulator by resin molding is adopted as an aluminum extrusion honeycomb and a bottom, and rigidity and a periodic-damping property are improved.
It excels in a transformer case at the shielding effect and a periodic-damping property, and cast iron with almost no resonance frequency is used. Moreover, it was filled up with the thermally conductive good pitch material between the case and the main unit of a transformer, and the incrementation in the resistor by a temperature rise is prevented by preparing a radiation fin.
Moreover, the balanced type volume shaft which made influence of an oscillation the minimum is used, and with the scheme which maintains the weight balance of bothways focusing on the bearing of the rotary knob of a volume, it considers so that a mechanical stress may not start a volume main unit.

Switching distortion makes non switching circuit type IBM PCN II which is not generated theoretically upgrade further, carries non switching circuit type dBASE III which separated clearly the power-source amplification stage and the power amplification stage, and is improving the speaker drive capacity at the time of a low load intensity.
Moreover, while stabilizing the idle current which is carrying out the drift by the temperature change etc. immediately after power-switch ON and at the time of the Taishin number input, the occurrence of thermal distortion is suppressed.

The original NF-CR type is adopted as a Phono equalizer, and the special feature of the frequency characteristic which was excellent in the large NF type dynamic range and CR type is reconciled.

By adoption of a Phono equalizer switchpoint, while not hearing the record, it is possible to turn OFF a circuitry, and an occurrence of an unnecessary noise can be suppressed.
Moreover, while playing an audio source, the V function-off switchpoint which can do the power source OFF of a video-system system is carried.

The polar attached-indicator oxygen-free-high-conductivity-copper power cord which considered the influence of external noise was used, and the nickel phosphorus plating which reduces nonlinear distortion is adopted as a power plug.
Furthermore, it plated with gold and the vice type which can do a current supply source with few losses in a speaker terminal is adopted as an input/output terminal.

Aluminum Naked material shaving appearance is adopted as a rotary knob.

The image system carries three inputs and three outputs, and mutual dubbing is possible for it.
In order that a video-system system may have an ill effect on an audio system and may prevent る, a power transformer for exclusive use is carried in video systems, and the circuitry and the grounding are separated.

Backplane
A
Input Chimney
The Hybrid

Rating of a mode
Form Stereo Integrated Amplifier
<Amplifier part>
Output power (20Hz - 20kHz, both channel drive) 180W+180W (4 ohm, 0.005%)
150W+150W (6 ohm, 0.003%)
120W+120W (8 ohm, 0.003%)
Dumping factor (1kHz, 8ohm) 200
Input sensitivity/impedance Phono man month: 2.5mV / 50kohm
Phono MC: 0.2mV/100 ohms
compact disk, Tuner, VDP, VCR, Tape:150mV /, 50kohm
Phono maximum permissible input (1kHz, 0.008%) MM:200mV
MC:19mV
An Output voltage/impedance Tape Rec and VCR Rec:150mV /, 2.2kohm
Frequency characteristic Phono man month: 20Hz-20kHz±0.2dB
Phono MC: 20Hz-20kHz±0.3dB
compact disk, Tuner, and Tape:1Hz-150kHz+0 -3 dB
S/N ratio (IHF, A network)
Short circuit
Phono MM:89dB(2.5mV
Phono MC:71dB(0.25mV)
compact disk, Tuner, VDP, VCR, DAT/Tape1, Tape2:110dB
<Composite video-system part>
Input sensitivity/impedance VDP, VCR 1 and 2, TV/AUX:1 Vp-p/75ohm
An Output voltage/impedance Monitor, VCR1, 2:1 Vp-p/75ohm
DG 2% or less
DP 2 degrees or less
Frequency characteristic 10Hz-10MHz+0 -1 dB
SN ratio 60dB or more
<S image terminal area>
Input sensitivity/impedance VDP, VCR 1 and 2
Luminance signal: 1 Vp-p/75ohm
Chrominance signal: 0.286 Vp-p/75ohm
An Output voltage/impedance VCR 1 and 2, Monitor
Luminance signal: 1 Vp-p/75ohm
Chrominance signal: 0.286 Vp-p/75ohm
Luminance-signal frequency characteristic 10Hz-10MHz+0 -1 dB
SN ratio 60dB or more
<Synthesis>
Supply voltage AC100V, 50Hz/60Hz
AC outlet Power-switch interlock: Two lines (200W)
Power-switch un-interlocking.: One line (100W)
Power consumption (Electrical Appliance and Material Control Law) 365W
Dimensions Width 459x height 173x depth of 471mm
Weight 28kg