I also got this:
It is a Hitachi HMA8300 and a Hitachi HCA8300 with some whopping 200Wpch into 8, but I don't know what is class G. It's back to the classroom.
On a later edit
)) I'm having a hard time finding the 4 Ohm rating.
I did find this for the preamp:
Input sensitivity/impedance:
Phono1: 2-6mV/50kohm
Phono2: 2mV/50kohm
Tuner, Aux1, 2, Tape1, 2: 100mV/50kohm
Maximum permissible input:
Phono1:400mV-1,200mV (RMS, 1kHz)
Phono2:400mV (RMS, 1kHz)
Tuner, Aux1, 2, Tape1, and 2: 10V
Output voltage/impedance:
Tape rec (pin): 100mV/600 ohms
Tape rec(din): 40mV/80kohm
Pre out: 1V/600 ohm
Headphone: 70mV/90 ohms
Maximum output level Pre out: More than 7V
Rec out: 20V
Frequency characteristic
(RIAA deflection) Phono1 & 2: 20Hz-20kHz±0.2dB
Tuner, Aux1 & 2: 5Hz-100kHz + 0 -1.5 dB
S/N (IHF, A network)
Phono 1 & 2: 75dB
Tuner, Aux1, 2, Tape1, 2: 100dB
Remains noise:
Pre out: 8 microvolts
Headphone: 40 microvolts
Distortion (20Hz - 20kHz):
Phono1 & 2 : 0.005% or less (1V) 0.01% or less (20V)
Tuner, Aux1 & 2 : 0.005% or less (1V) 0.01% or less (7V)
Tone control:
Bass: ±10dB
Turnover frequency: 150Hz, 300Hz
Treble: ±10dB
Turnover frequency: 3kHz, 6kHz
Filter:
Low: 20Hz, 12dB / oct
High: 8kHz, 6dB / oct
Loudness control:
(Volume -30dB) +8dB(100Hz)
+4dB(10kHz)
Gain selector: - 5, -10, -20dB
Supply voltage AC100V, 50Hz/60Hz
AC outlet Power-switch interlock: Two lines
Power-switch un-interlocking.: Two lines
Power dissipation: 9.5W
Dimensions: Width 435x height 152x depth of 308mm
Weight: 6.5kg