HITACHI/Lo-D HA-660
¥ 72,600 (around 1974)
Commentary
A pre-main amplifier developed with the concept of pursuing not only physical characteristics but also musical characteristics.
The driver stage of the main amplifier section is driven by constant current to eliminate crossover distortion and distortion caused by Oire force.
The equalizer amplifier section uses Hi-Fi dedicated transistors and 3-stage direct-coupled circuits to obtain a dynamic margin of more than 40 dB.
Each operation of the amplifier stage and bare characteristics of the overall are checked to reduce distortion.
Model Rating
| Type | Pre-main amplifier |
| Effective output (both channel drive) | 32W + 32W (8 Ω) |
| Music Power (IHF) | 100W (8 Ω) |
| Distortion | 0.5% (Effective Output) 0.03% (at 10W output) |
| Damping factor | 50 (1 kHz, 8 Ω Load) |
| Input Sensitivity / Impedance | Phono1 Low : 2mV/50k Ω Phono1 High : 5mV/50k Ω Phono2 : 2mV/50k Ω Aux1, 2, Tuner, Tape1, 2 : 100mV/50k Ω |
| Recording output sensitivity | Rec out:100mV Din out:30mV |
| Signal-to-noise ratio | Phono1:70dB Phono2:65dB Aux1, 2, Tuner : 85 dB |
| Tone control | Bass : ± 10 dB (100 Hz) Treble : ± 10 dB (10 kHz) |
| Filter | -6dB(30Hz)12dB/oct -6dB(10kHz)12dB/oct |
| Attachment | Speaker switching Audio Muting AC Outlet Route 3 Two tape decks can be connected |
| Semiconductor used | Transistor : 29 Diode : 14 pcs |
| External dimensions | Width 432x Height 142x Depth 340 mm |
| Weight | 10.2kg |