VICTOR/JVC A-X55
¥ 75,000 (released in 1982)
Made In Japan

https: //audio-database.com/VICTOR/amp/a-x55.html

Type Pre-main amplifier
Circuit System
Equalizer amplifier section Pure NFB / ICL / DC servo, MC/MM equalizer amplifier with first stage EL-FET cascode bootstrap
Power amplifier section Power Amplifier with Dynamic Super A, Pure NFB / ICL / DC First Stage Dual FET Cascode Bootstrap
Power supply part Direct power supply (power stage)
Shunt lock power supply (equalizer stage)
Overall Characteristics
Effective power
(Tuner, Aux, Tape → Spout) 80W + 80W (20 Hz ~ 20 kHz, 8 Ω, THD0.003%)
83W + 83W (1 kHz, 8 ω, THD0.0007%, By HP-IB Audio Analyze System)
Total harmonic distortion factor (at effective output)
Tuner, Aux, Tape → Spout :

Phono MM → Spout : 0.003% (20 Hz to 20 kHz, 8 Ω)
0.0007% (1 kHz, 8 ω, By HP-IB Audio Analyze System)
0.02% (5 Hz ~ 60 kHz, 8 Ω)
0.007% (20 Hz to 20 kHz, 8 Ω, Vol-30dB)
Cross modulation distortion factor 0.002% (60 Hz : 7 kHz = 4 : 1, effective output, 8 Ω, Tuner, Aux, Tape → Spout)
Switching distortion 0
TIM Distortion 0(LPF fc=100kHz)
Output bandwidth 5 Hz ~ 60 kHz (IHF, both channel operation, 8 Ω, THD0.02%, Tuner, Aux, Tape → SPOUT)
Frequency characteristic DC ~ 300 khz + 0 -3dB (8 Ω, Tuner, Aux, Tape → Spout)
Damping factor 150 (1 kHz, 8 Ω, Tuner, Aux, Tape → Spout)
Input Sensitivity / Impedance
(1kHz) Phono MM : 2.5mV/47k Ω
Phono MC : 180 μ V/100 Ω
Tuner, Aux, Tape1/2 : 160mV/47k Ω
Signal-to-noise ratio Phono MM : 86 dB (IHF A-202 84 dB, Rec out)
Phono MC : 70 dB (250 μ V input, IHF A-202 76 dB, Rec out)
Tuner, Aux, Tape : 110 dB (IHF A-202 84 dB, SP out)
Tone control Bass : ± 8 dB (100 Hz)
Treble : ± 8 dB (10 kHz)
Subsonic filter 18 Hz, -6dB/oct.
Loudness + 6 dB (100 Hz), + 4 dB (10 kHz)
Muting -20dB
Equalizer amplifier section (Phono → Rec out)
Phono maximum allowable input Phono MM : 250 mV (1 kHz, THD0.0008%)
Phono MC : 15 mv (1 khz, 0.001% THD)
RIAA deviation 20 Hz to 20 kHz ± 0.2 dB
Total harmonic distortion factor Phono MM : 0.004% (20 Hz to 20 kHz at 8 V output)
Phono MC : 0.008% (20 Hz to 20 kHz at 8 v output)
Output Voltage / Impedance Rec out : 160mV/660 Ω