TRIO TW-31
¥ 22,000 (around 1967)
Commentary
This small pre-main amplifier was developed with the aim of making it as small as possible while maintaining performance taking advantage of the features of solid state.
The output circuit uses the OTL method of ITL-SEPP with silicon transistors.
Therefore, the output transformer is removed.
It also has a purely electronic protection circuit to protect the power transistors.
It is equipped with functions such as stereo headphone switch, tape monitor, CR tone control and loudness.
Model Rating
| Type | Solid state stereo pre-main amplifier |
| Effective power | 13W/13W (8 Ω, 0.5% strain) |
| Music Power (1% distortion) | 40W (4 Ω) 35W (8 Ω) |
| Frequency characteristic | 20 Hz to 50 kHz ± 1 dB |
| Output band characteristics (distortion 1%, effective output) | 20 Hz to 60 kHz -3dB |
| Distortion Factor (1 kHz) | 0.3% or Less (Output 9W/9W) 0.15% or Less (Output 3W/3W) 0.2% or Less (Output 0.3W/0.3W) |
| Gain / Impedance (effective output, 1 kHz) | MAG : 2.1mV/100k Ω Tuner, AUX1, 2, Tape Play : 130mV/50k Ω |
| Tone control | 100 Hz : + / - 11 dB 10 kHz : ± 11 dB |
| Loudness control (Volume -30dB) | + 9 dB (100 Hz), + 3 dB (10 kHz) |
| Equalizer | RIAA |
| SN ratio (volume maximum, tone control flat) | MAG : 65 dB or more Tuner, AUX1, 2, Tape Play : 75 dB or higher |
| Residual noise (minimum volume) | 1 mV or less (8 Ω load) |
| Damping factor | 20 or More (8 Ω) |
| Accessory circuit | Tape monitor switch Loudness control CR Type Tone Control Stereo headphone jack USAPAT Protection Circuit |
| Semiconductor used | Transistor : 19 Diode : 8 pcs |
| Power supply voltage | 100 VAC, 50Hz/60Hz |
| Power consumption | No signal : 20W Maximum output : 60W |
| External dimensions | Width 260x Height 105x Depth 237 mm |
| Weight | 4.5kg |