Audio Database

Image of SA-710

Stereo pre-main amplifier using pure complimentary service OCL ocL system directly connected to all stages.

The equalizer uses a carefully selected PNP type low-noise transistor for the first stage and a 3-stage direct amplifier with an emitter follower circuit for the second stage.
The high gain of the first stage satisfies the requirements for a low-noise, high-gain head amplifier.

In order to completely suppress the deviation of the RIAA playback curve, the NFB element of the equalizer and the element of the part receiving NFB use nichrome evaporated metal film resistance with 1% error and styrene capacitor with 2% error.

In the control amplifier section, an FET with high input impedance is used for the first stage, so no noise change occurs regardless of the adjustment position of the volume control.

Bass and Treble are equipped with independent turn-over switches, each of which can independently select the turn-over frequency, so you can control the tone according to the characteristics and effect of the source.

Equipped with a tone defeat switch that can select tone flat with one touch regardless of the turnover position or tone characteristics.

The power circuit uses a direct-coupled pure complimentary service OCL system for all one stage differentials.
In addition to the one stage differential amplifier, the bias temperature guarantee circuit at the first stage provides sufficient DC stability, so that the 0 potential at the output point does not collapse even with large temperature changes.
In addition, the use of a large radiator and a power transistor with high breakdown strength provides a high degree of safety, and high power is obtained in a stable state.

PNP and NPN transistors with the same pair characteristics are used for the driver and power transistor.
In addition, the use of a large radiator, a current limiting circuit, and an electronic protective circuit increases the safety level.

There are two circuits for the TapeMon jacks, and duplication is also possible.
In addition, it is equipped with a two circuit speaker terminal which can play A, B, A + B individually or in combination.

It has a built-in subsonic filter (5 Hz, 12dB/oct) to cut unwanted noise in the ultra low frequency range.

The protective circuit is a combination of an electronic circuit and a power relay. An indicator lights when the protective circuit is activated.
It also serves as a power muting to eliminate shock noise when the power supply is turned on.

Attached is the measured data for each unit.

Model Rating
Type Stereo pre-main amplifier
Power Amplifier Unit
Circuit system Pure complimentary service OCL
Effective power
20 Hz to 20000 Hz, both channel drive : 20W + 20W (8 Ω)
24W + 24W (4 Ω)
1 kHz, both channel drive : 22W + 22W (8 Ω)
30W + 30W (4 Ω)
1 kHz, single-channel drive : 25W/25W (8 Ω)
36W/36W (4 Ω)
Harmonic distortion factor Effective power : 0.5% or less
1W output : 0.05% or less
Cross modulation distortion factor Effective power : 0.5% or less
0.1% or less at 1W output
Output Bandwidth (IHF, both channel drives) 5 Hz ~ 70 kHz (Distortion Factor 0.5%)
Frequency characteristic 7 Hz to 80 kHz, + 0 -1dB
Input Sensitivity / Impedance Power Amp In : 500mV/50k Ω
Output terminal Speaker : A, B, A + B (4 Ω ~ 16 Ω)
Head Phones : 4 Ω ~ 16 Ω
Damping factor (1 kHz, 8 Ω) 40 or more
S/N 90 dB or more (IHF, short circuit A network)
Residual noise (8 Ω, pre + power amplifier) 1 mV (0.13 μ W) or less
Subsonic filter 5Hz(12dB/oct)
Preamplifier Section
Circuit system Equalizer amplifier : 3-stage direct connection NF type
Control amplifier : First stage FET, NF type
Input Sensitivity / Impedance Phono1 : 2.5mV/50k Ω
Phono2 : 2.5mV/50k Ω
Phono maximum allowable input (rms/p-p) : 190mV/530mV
MIC : 2.0mV/50k Ω
Tuner : 150mV/100k Ω
AUX1 : 150mV/100k Ω
AUX2 : 150mV/100k Ω
Tape Monitor1, 2 : 150mV/100k Ω
Tape Monitor2 (DIN) : 150mV/100k Ω
Output Level / Impedance Tape Rec1, 2 : 150 mv
Tape Rec2 (DIN) : 30mV/80k Ω
Pre Out : 500mV/1.5k Ω
Harmonic distortion factor (20 Hz to 20 kHz) Not more than 0.1%
Frequency characteristic Phono (RIAA deviation) : 30 Hz to 15 kHz, ± 0.2 dB
MIC : 15 Hz to 10 kHz, + 0 -1dB
Tuner, AUX, TapeMonitor : 15 hz to 30 khz, + 0 -1dB
Tone control
Bass ± 6.5 dB (100 Hz)
± 10 dB (100 Hz)
Turnover frequency : 200 hz, 400 hz
Treble ± 7.5 dB at 10 kHz
± 10.5 dB at 10 kHz
Turnover frequency 5 kHz, 2.5 kHz
Loudness contour at volume -40dB + 10 dB at 100 Hz, 6 dB at 10 kHz
S/N (IHF, short circuit)
A network)
Phono : 80 dB or more
MIC : 70 dB or more
Tuner, AUX, Tape Monitor : 90 dB or higher
Muting -20dB
Semiconductor used FET:2
Transistor : 33
Diode and others : 24
Power supply voltage 100 VAC, 50Hz/60Hz
Rated power consumption 55W
Maximum Power Consumption 180W
Power outlet Power switch interlock 1, non-interlock 2
External dimensions Width 430x Height 138x Depth 341 mm
Weight 10.1kg