VICTOR/JVC JA-S55
¥ 65,000 (around 1978)
Commentary
A pre-main amplifier that adopts a tri-DC circuit by converting all stages to DC amplifiers.
The equalizer has a DC configuration using a pair FET at the first stage.
The ICL circuit using FET improves the characteristics when the cartridge is actually connected.
The tone amplifier uses a DC configuration circuit with FET and ICL inputs ICL inputs to realize a low distortion factor that is almost the same as that of the tone defeat.
All stages are directly connected DC amplifier configuration for the power amplifier section.
The power supply section has a direct power supply chassis structure. The power supply for the Class B stage is equipped with a rectifier circuit on the left and right independently and integrated with the output stage. This reduces the power supply impedance over a wide band, prevents magnetic field lines from jumping due to a large current, and reduces distortion.
A recording / re-terminal is mounted on the front.
Uses low distortion rate multi-contact volume.
Equipped with a logarithmic compression type power meter.
Equipped with 3 Oshige point protection circuit with independent detection on right and left.
.JPG)
Model Rating
| Type | Pre-main amplifier |
| Power Amplifier Unit | |
| Circuit system | Fully connected full DC amplifier |
| Effective output (when both channels operate) | 60W + 60W (8 Ω, 20 Hz to 20 kHz, THD0.02% or less) 70W + 70W (4 ohm, 1 khz, THD0.05%) |
| Total harmonic distortion factor | 0.02% or Less (8 Ω at Effective Output, 20 Hz to 20 kHz) 0.005% or Less (1 kHz) |
| Cross modulation distortion factor | 0.01% or Less (8 Ω at Effective Output) |
| Frequency characteristic | 5 Hz ~ 100 kHz + 0 -1dB from Aux Input |
| Preamplifier Section | |
| Circuit system | All stages DC configuration, first stage FET differential ICL, class A operation |
| Input Sensitivity / Impedance | Phono : 2.5mV/47k Ω Tuner, Aux, Tape play : 200mV/50k Ω |
| RIAA deviation | 20 Hz to 20 kHz ± 0.3 dB |
| Phono maximum allowable input | 230 mv (RMS, 1 kHz) |
| Frequency Response (Aux) | 5 Hz to 100 kHz + 0 -1dB |
| SN ratio (IHF-A short circuit) | Phono:81dB Aux:105dB |
| Power Supply Unit and Others | |
| Circuit system | Class A and Class B Independent, direct power supply system |
| Rated power consumption (Electrical Appliance and Material Control Law) | 154W |
| External dimensions | Width 420x Height 149x Depth 334 mm |
| Weight | 10.0kg |