Pioneer SM-101
¥ 49,800 (around the early 1970 s?)
Commentary
This is a stereo power amplifier designed to be used by enthusiasts.
In order to obtain a low distortion factor and uniform power over a wide range, a pure complimentary service OCL circuit directly connected to all stages is adopted.
A pair of triple-diffused power transistors with high breakdown strength for both PNP and NPN, developed for high output power, is used.
In order to stabilize the DC potential, two differential amplifiers are used.
Together with the temperature compensation circuit, stability is increased.
The protection circuit is a unique combination of relays and electronic circuits (8 transistors, 10 diodes).
When the DC balance of the output stage is lost and the DC component flows, the differential amplifier detects this and cuts the relay circuit to prevent the DC from flowing to the speakers.
Also, when the output terminal of the speaker is short-circuited or excessive current flows in the output stage, the AC component of the output stage is detected and the relay circuit is turned off to protect the power transistor.
When the power switch is turned on, it acts as a mute to prevent unpleasant noise from the speakers.
The indicator on the front panel blinks when the protector is operating.
An output level meter is mounted on the front panel.
The sensitivity of the meter can be switched to five positions : Off, 0 dB, -10dB, -20dB and -30dB.
Two input systems are installed, and can be switched with the front switch.
In addition, it is equipped with an input sensitivity selector of constant input impedance, and 4 positions can be switched as needed.
Equipped with left and right independent speaker phase change switches.
There are two types of speaker output jacks, which can be switched between A, B, or A + B using the selector.
The characteristic data of each unit is attached.
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Model Rating
| Type | Stereo power amplifier |
| Circuit system | All-stage direct-coupled complimentary service OCL circuit |
| Music Power (IHF) | 240W (4 Ω) 170W (8 Ω) |
| Effective power | Single channel drive 70W/70W (8 Ω) 90W/90W (4 Ω) Both channel drive 60W + 60W (8 Ω) 78W + 78W (4 Ω) 20 Hz ~ 20000 Hz Output (Both Channels Driven) 50W + 50W (8 Ω, Distortion Factor 0.15% or Less) |
| Harmonic distortion factor | 0.1% or Less (Effective Output) 0.05% or Less (8 Ω, 35W/35W Output) |
| Cross modulation distortion factor | 0.1% or Less (Effective Output) 0.06% or Less (8 Ω, at 35W/35W output) |
| Output Bandwidth (IHF) | 5 Hz to 30000 Hz |
| Frequency characteristic | 8 Hz to 70000 Hz, + 0 -1dB |
| Input Sensitivity / Impedance (Effective Output, 1 kHz) | 0.5 V, 1 V, 2 V, 5V/50k Ω |
| Load impedance | 4 Ω ~ 16 Ω |
| Damping factor | 40 (8 Ω, 1 kHz) |
| Hum and noise (IHF short circuit) | 95 dB or more |
| Meter sensitivity selector | OFF, 0 dB, -10dB, -20dB, -30dB |
| Level meters (L, R) | 0 db = 70W/8 Ω |
| Semiconductor used | Transistor : 26 Diode : 24 Others |
| Power supply voltage | 100 VAC, 50Hz/60Hz |
| Rated power consumption | 125W |
| Maximum Power Consumption | 330W |
| Power outlet | Linkage : 1 system Non-linked : 1 system |
| External dimensions | Width 430x Height 144x Depth 337 mm |
| Weight | 10.7kg |