Audio Database

The

Technics SE-9200
120,000yen (around the 1975 time)

Description
 
Stereo power amplifier which carries a 4 steps of Output-load-impedances change.

An Output load impedance can be switched to four steps, 0.08ohm (normal), 0.8ohm, 2.7ohm, and 8ohm. The circuitry serves as a bridge scheme without a gain transition.
A dumping factor is changeable with this Output-load-impedance change, and it is possible to pull out the performance of a speaker more and it becomes the numeration which is switched to 100, 10, 3, and 1 in the case of an 8-ohm speaker.

The circuitry of the power amplifier part is based on differential-amplification whole page hardwired-connection perfect complimentary OCL, and the work which realizes a low distortion and a high stability amplification everywhere is carried out.

While inserting the emitter-follower in the differential-amplifier following stage, increasing first rank amplification degree to it and improving an SN ratio, the impedance matching to the predrive stage was rationalized, and the distorted occurrence is prevented.
Moreover, in the predrive stage, while removing a bootstrap capacitor and raising low-pass stability, the stability of the output stage is also raised.

A power-source part adopts the constant-voltage regulated power supply of ±42V as the voltage amplification stage, and has adopted a mass transformer and a 10,000-micro F capacitor as an output stage.

The output Direct-reading peek detection type power meter is carried.
This meter can adjust three steps of meter range, and can read the movement toward an output in a higher precision.

The protection network original with technics by relay is adopted.
In this circuitry, relay contact resistance does not go into a signal system, and years of using does not have a tone-quality failure, either.

As a shocking noise insulator circuitry at the time of the power source ON, the zener diode of the common-emitter power source of a differential amplification, diode, the capacitor, and the timing circuit constituted from a resistor are carried.

Rear

Rating of a mode
Form Stereo power amplifier
Effective output A one side channel, 1kHz:110W/110W (4ohms)
83W/83W (8ohms)
Both channel, 1kHz:103W+103W (4ohms)
82W+82W (8ohms)
Both channel, 20Hz-20kHz:93W+93W (4ohms)
76W+76W (8ohms)
THD 0.08%
Output bandwidth 5Hz - -70kHz three dB (both ch(es), 8ohms)
Frequency characteristic 5Hz-100kHz+0 -3 dB
SN ratio 110dB
Remains noise 0.3mV
Dumping factor 4ohm: 50, 5, 1.5, 0.5
8ohm: 100, 10, 3, 1
Load impedance Main or Remote: 4ohms - 16ohms
Main+Remote: 8ohms - 16ohms
Input sensitivity/impedance 1V/40kohm
Power source AC100V, 50Hz/60Hz
Power consumption 180W
Dimensions Width 450x height 173x depth of 380.5mm
Weight 15kg