Audio Database

Image of SA-80
Commentary

Pre-main amplifier with all stages directly connected circuit.

The power amplifier section uses a 2-power supply system OCL circuit directly connected to all stages.
Since no coupling capacitor or output capacitor is used between each stage, the small inductance of the capacitor does not adversely affect the wide-range characteristics. Moreover, there are no unstable elements such as oscillation caused by the coupling capacitor. Therefore, a large amount of NF can be applied, and the distortion is kept low over the band.

The protection circuit is a combination of one power relay, seven transistors, and nine 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 protect the speakers.
In addition, in the event of a trouble such as short-circuiting the speaker terminals or excessive current flowing in the output stage, the AC component of the output stage is detected and a protective circuit operates to protect the power transistor.
This protection circuit also functions as a power muting, so that noise at the time of power-on is suppressed.
In addition, this protection circuit is automatic recovery type, so it returns to normal condition when the trouble is solved.

The head amplifier uses a 3-stage direct connection EE feedback circuit.

The control amplifier uses a 3-stage direct-coupled circuit with a low-noise FET at the first stage.
In addition, since the NFB circuit uses a tone selector to switch the elements in the circuit, accurate tone control is possible in 3 db steps.
When the tone control is in the flat position, the tone is completely canceled.

Equipped with Low and High filters with cutting characteristics of 12dB/oct.
This eliminates unpleasant sounds at low frequencies, such as motor gobos and the hum component of program sources, and noise at high frequencies, such as record scratch noise.

Equipped with two tape input / output systems.

Two systems of Phono input terminals are mounted.
The Phono2 has a MM-MC changeover switch and uses MC cartridges in addition to MM cartridges.
In addition, by using the transformer for MC cartridge sold separately, it becomes possible to reproduce with higher quality MC cartridge.

A microphone input jack is installed on the front panel.
Two AUX inputs are installed.

Equipped with an audio muting switch that lowers the output level by 20 dB.

A switch on the rear panel allows you to separate the preamp and power amp sections.

Center channel terminal for extracting L + R signal is mounted.

Model Rating
Type Stereo pre-main amplifier
Power Amplifier Unit
Circuit system OCL system for all stages connected with semi-solid complimentary service
Music Power (IHF) 108W (8 Ω)
165W (4 Ω)
Effective power
Single-ch drive : 41W/41W (8 Ω)
53W/53W (4 Ω)
Both channel drive : 34W + 34W (8 Ω)
39W + 39W (4 Ω)
20 Hz to 20 kHz output, both channel drive : 26W + 26W (8 Ω, Distortion Factor 0.5% or Less)
Harmonic distortion factor 0.5% or Less (Effective Output)
Cross modulation distortion factor 0.5% or Less (Effective Output)
Output bandwidth 5 Hz to 50000 Hz
Frequency characteristic 5 Hz to 80000 Hz ± 1 dB
Input Sensitivity / Impedance 560mV/100k Ω
Load impedance 4 Ω ~ 16 Ω
Damping factor 65 or More (8 Ω, 1 kHz)
Center channel output voltage 500mV
Preamplifier Section
Output voltage 3 v (rated)
5 v (max)
Harmonic distortion factor Not more than 0.1%
Frequency characteristic 20 Hz to 60000 Hz ± 1 dB
Input Sensitivity / Impedance
Phono1 MAG : 3mV/50k Ω
CER : 56mV/100k Ω
Phono2 MAG : 3mV/50k Ω
MC : 110 μ V/30 Ω (Separately Sold Transformer PP-402 Used)
MIC : 2.3mV/25k Ω
Tuner : 230mV/200k Ω
AUX1, 2 : 230mV/200k Ω
Tape Mon1, 2 : 230mV/200k Ω
Recorded output Tape Rec1, 2 (pin jack) : 230 mv
DIN re-connector : 35 mv
Tone control 3 dB step
Bass : -9dB to + 12 dB (100 Hz)
Treble : -12dB to + 9 dB at 10 kHz
Filter Low : -3.5 dB (60 Hz), 12dB/oct.
High : -3dB (6 kHz), 12dB/oct.
Equalizer (Phono) NFB Type RIAA
Loudness (volume -40dB) + 11.5 dB (100 Hz), + 6.5 dB (10 kHz)
Signal-to-noise ratio (IHF) Phono : 80 dB or more
AUX : 100 dB or more
Channel separation Phono : 50 or higher
Tuner, AUX : 55 or higher
<General>
Semiconductor used FET : 2
Transistor : 35
Diode : 20 pcs
Power supply voltage 100 VAC, 50Hz/60Hz
Rated power consumption 105W
External dimensions Width 430x Height 145x Depth 337 mm
Weight 10.8kg