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TOSHIBA SB-404/SB-404S
SB-404 : ¥ 69,800 (around 1973)
SB-404S : ¥ 71,800 (around 1973)
Commentary
A 4-channel pre-main amplifier with a 4-channel decoder.
SB-404 is equipped with QM method decoder unit (in some catalogs, RM method was described instead of QM method).
Also, the SB-404S is equipped with an SQ decoder as the upper model.
It is equipped with an independent premain circuit and can be used as a discrete 4-channel system by connecting a 4-channel deck. It can also be used as a CD-4 system by connecting a demodulator (SY 504).
The pre-main circuit consists of four independent systems.
The transistors used in the circuit are 2SC1000 ultra-low noise transistors manufactured by Toshiba. This transistor is manufactured by PCT manufacturing method (Perfect Crystal Device of Technology) and has excellent characteristics such as 1/2 at 100 Hz and 1/3 at 10 kHz compared with conventional low-noise transistors.
The SB-2SC1000 uses a total of 27 2SC1000 units for all circuits in 404 s.
An equalizer circuit for capacitor cartridges is built in.
This makes it possible to use Toshiba Record Player SR-80C and Electret Type Condenser Cartridge C-401S series.
The power amplifier circuit uses an OCL-type IC power pack directly connected to all stages.
By making all stages directly coupled, deterioration of various characteristics due to coupling capacitors is prevented, and frequency characteristics and strain characteristics are improved.
BTL connection is available for 2-channel playback, and output can be increased by using four power amplifiers.
Model Rating
| Type | 4-channel pre-main amplifier |
| Main Amplifier Section | |
| Effective output (distortion 0.4%) | 26W + 26W (8 ohm, BTL) 15Wx4 (8 Ω) |
| Music power (IHF, 0.8% strain) |
30W + 30W (8 ohm, BTL) 17Wx4 (8 Ω) |
| Total harmonic distortion factor | 0.4% (8 Ω at Rated Output) |
| Cross modulation distortion factor | 0.8% (8 Ω at Rated Output) |
| Frequency characteristic | 10 Hz ~ 55 kHz + 0 -3dB |
| Input Sensitivity / Impedance | Main in : 0.5V/37k Ω |
| Residual noise | 0.5 mv (8 Ω) |
| Damping factor | 20 (8 Ω) |
| Speaker impedance | 4 Ω ~ 16 Ω (8 Ω ~ 16 Ω at BTL) |
| Preamplifier Section | |
| Input Sensitivity / Impedance | Phono1 MAG : 2.5mV/47k Ω Phono1 cc : 30mV/70k Ω Phono2 : 2.5mV/47k Ω Tuner : 150mV/47k Ω Aux1 (4 ch), Aux2 (4 ch) : 150mV/47k Ω 4 ch Tape : 500mV/47k Ω |
| Output level | Tape rec:150mV Din:30mV Pre out : 0.5 v (max. 4.2 v) |
| Frequency characteristic | 5 Hz ~ 100 kHz + 0 -3dB |
| Total harmonic distortion factor | 0.04% (at rated output) |
| Maximum Input Voltage (1 kHz) | Phono MAG:100mV Phono CC:1.2V |
| Tone control | Bass : ± 10 dB (100 Hz) Treble : ± 10 dB (10 kHz) |
| Equalizer deviation | ± 0.5 dB for RIAA |
| Signal-to-noise ratio | Phono:65dB(2.5mV) CC:70dB(30mV) Aux:80dB(150mV) |
| <General> | |
| Semiconductor used | IC : 5 Transistor : 27 Diode : 10 pcs |
| Pwer | AC100V/120V/220V/240V, 50Hz/60Hz |
| Power consumption | 60W maximum 16W (no signal) |
| External dimensions | Width 400x Height 115x Depth 280 mm |
| Weight | 7.5kg |
