ONKYO A-812EX
¥ 43,000 (released in June 1987)
Commentary
A pre-main amplifier with low impedance drive capability by discrete output stage using large power supply circuit and HighfT power transistor.
It is equipped with a CD direct switch, which bypasses the input selector and other switches and the circuit part such as tone control, and amplifies the signal from the CD player by sending it directly to the power amplifier section.
To prevent unwanted interference with the analog part of the digital signal, the CD input is equipped with S. I. T. (signal in phase transformer) to eliminate digital noise in the high frequency band without affecting the music signal.
The CD terminal uses a gold-plated type with a particularly low resistance value.
Twin Turbo Tone Control is installed to make the most of the appeal of the digital source and enhance the realism.
By pressing the Twin Turbo switch, it is possible to enhance the ultra-low band around 50 Hz, which is even lower than the Bass band. It provides balanced tone control that enhances the power of the bass instrument without masking the mid-range, while at the same time supplementing the high-range.
The Phono input is equipped with an MC/MM changeover switch and is compatible with MC cartridges.
A linear switching method is adopted to reduce crossover distortion.
A delta turbo power supply is also installed to eliminate noise from the AC line.
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Model Rating
| Type | Pre-main amplifier |
| Maximum practical power | 105W + 105W (6 ohm, EIAJ) |
| Rated Output (CD → SP Out, both channels driven) | 72W + 72W (6 Ω) 60W + 60W (8 Ω) |
| Dynamic Power | 135W + 135W (2 Ω) 78W + 78W (8 Ω) |
| Total harmonic distortion factor | 0.08% or Less (at 1 kHz, Rated Output -3dB) |
| S/N ratio (IHF-A, short) | Phono MM:83dB Phono MC:65dB CD, Tuner, AUX/Video, Tape, DAT : 90 dB |
| Phono maximum allowable input | MM : 150 mV (1 kHz, 0.5%) |
| Tone control | Bass : ± 10 dB (100 Hz) Treble : ± 10 dB (10 kHz) Twin Turbo : ± 15 dB (50 Hz), ± 6 dB (10 kHz) |
| Muting | -20dB |
| Speaker switching | A, B, A + B |
| Input Sensitivity / Impedance | Phono MM : 2.5mV/50k Ω Phono MC : 0.35mV/330 Ω CD, Tuner, AUX, Tape, DAT : 150mV/50k Ω |
| Power supply voltage | 100 VAC, 50Hz/60Hz |
| Power consumption (Electrical Appliance and Material Control Law) | 115W |
| External dimensions | Width 435x Height 120x Depth 272 mm |
| Weight | 6.7kg |