Pioneer - SX-690 Solid state stereo amplifier

stereo receiver Pioneer SX-680,
a vintage audio amplifier/receiver manufactured by Pioneer in the late 1970s (around 1978–1980). side panels made of a material that imitates black marble with white veins.
It is a classic hi-fi unit from the golden age, with an AM/FM radio tuner, an integrated amplifier of about 30 watts per channel, tone controls (bass, treble, balance), an input selector, and a headphone output. It is highly regarded by analog audio enthusiasts for its warm sound and sturdy construction.
Amplification
• Output power: 30 watts per channel RMS (continuous) at 8 ohms (stereo).
• Total harmonic distortion (THD): 0.1% (or less).
• Intermodulation distortion: Less than 0.1%.
• Damping factor: 25.
• Frequency response: 5 Hz to 100 kHz.
• Minimum speaker impedance: 4 ohms.
Inputs and Sensitivity
• Input sensitivity:
• Phono (MM): 2.5 mV.
• Line (Aux, Tape): 150 mV.
• Signal-to-noise ratio (SNR):
• Phono (MM): 75 dB.
• Line: 90 dB.
• Line output: 150 mV.
Tuner
• Bands: FM and AM (MW).
• FM sensitivity: Approximately 1.9 μV (good reception).
General characteristics
• Controls: bass, treble, balance, loudness, input selector (Phono, Aux, Tape, Tuner), high/low filter.
• Illuminated analog power meters.
• Headphone output.
Robust construction with a metal chassis and a silver front panel.
Dimensions and weight
• Dimensions: 435 mm (width) × 144.5 mm (height) × 314 mm (depth).
• Weight: 8.9 kg.
This receiver stands out for its warm and powerful sound for its size, ideal for vintage hi-fi systems. It is highly regarded for its Japanese build quality and its sensitive FM tuner. If you use it today, it pairs well with efficient 8-ohm speakers.

Minimal signs of use.