ROTEL RA-1210
¥ 73,000 (around the early 1970 s)
Commentary
A pre-main amplifier that uses a fully separate two power supply system for the main amplifier (a transformer and a capacitor that are independent for the left and right channels).
All stages are directly connected OCL quasi complimentary service using one stage of differential amplifier for main amplifier circuit.
Since there is no output capacitor, a stable output with little distortion can be obtained from the low to high range.
3-stage direct connection E-E feedback with only PNP type transistor is adopted.
Because the power supply voltage is not in steady state for 5 to 6 seconds after the power is turned on, pop noise appears, and if pulse noise comes in, the speaker may be damaged.
To cope with this, there is a delay circuit and a fuse in each power circuit and a circuit breaker in each speaker circuit.
Since the circuit breaker is automatically reset, it will return after a while even if it works when it is overloaded.
Model Rating
| Type | Solid-state stereo amplifier |
| Main Amplifier Section | |
| Music Power (IHF) | 4 Ω : 230W 8 Ω : 160W |
| Effective power (RMS) | 4 Ω : 80W + 80W 8 Ω : 60W + 60W |
| Harmonic distortion factor | Rated output : 0.5% 55W output : 0.1% (20 Hz to 20000 Hz) |
| Cross modulation distortion factor | 55W output : 0.1% |
| Frequency characteristic | 3 hz to 100,000 hz, + 0 -3dB |
| Output band characteristic | 5 Hz to 50,000 Hz |
| Damping factor | 35 (8 Ω) |
| Input Sensitivity / Impedance | 1V/30k Ω |
| Speaker impedance | 4 Ω ~ 16 Ω |
| Preamplifier Section | |
| Output voltage | 1 V ~ 3 V |
| Harmonic distortion factor | 0.1% |
| Frequency characteristic | 3 Hz to 50,000 Hz, + 0 -3dB |
| Signal-to-noise ratio | Phono1, 2 : 70 dB AUX1, 2, Tape In : 80 dB |
| Residual noise | 0.5mV |
| Input Sensitivity / Impedance | Phono1 : 1mV/100k Ω Phono2 : 1, 2, 4mV/30, 50, 100k Ω Tuner, AUX1, 2, Tape In : 180mV/45k Ω Tape DIN : 330mV/100k Ω |
| Equalizer | Within ± 0.5 dB deviation from RIAA standard curve |
| Loudness | 50Hz:+6dB 10kHz:+2dB |
| High filter | 10kHz:-10dB |
| Low filter | 50Hz:-10dB |
| Muting | 10kHz:-20dB |
| Bass | 50 Hz : + / - 10 dB |
| Treble | 10 kHz : ± 10 dB |
| <General> | |
| Power supply voltage | 100 V, 117 V, 220 V, 240 V, 50Hz/60Hz |
| Power consumption | 150W |
| External dimensions | Width 420x Height 140x Depth 304 mm |
| Weight | 13.7kg |