Harman Kardon HK 670 receiver - Stainless steel

vintage stereo receiver from 1979 with specs that include 60 watts per channel into 8Ω8Ω (though some sources list 8080watts) and an ultrawide frequency response from 3Hz3𝐻𝑧 to 140kHz140𝑘𝐻𝑧. It features a low total harmonic distortion of 0.03%0.03%at 1kHz1𝑘𝐻𝑧 and includes a phono input for turntables, as well as a subsonic filter and loudness control. It also has input sensitivity for MM (2.2mV2.2𝑚𝑉) and line (130mV130𝑚𝑉) sources and a signal-to-noise ratio of 90dB90𝑑𝐵 (MM) or 102dB102𝑑𝐵 (line). Amplifier specs 

• Power output: 60 watts per channel into 8Ω8Ω (some sources state 80 watts)
• Frequency response: 3Hz3𝐻𝑧 to 140kHz140𝑘𝐻𝑧 (-3.0 dB)
• Total harmonic distortion: 0.03%0.03% at 1kHz1𝑘𝐻𝑧
• Intermodulation distortion: 0.05%0.05% at rated output
• Damping factor: >30>30 at 8Ω8Ω 

Input and performance 

• Input sensitivity: 2.2mV2.2𝑚𝑉 (MM), 130mV130𝑚𝑉 (line)
• Signal-to-noise ratio: 90dB90𝑑𝐵 (MM), 102dB102𝑑𝐵 (line)
• Speaker load impedance: 8Ω8Ω to 16Ω16Ω
• Features: Phono stage for turntables, subsonic filter, loudness control 

Physical characteristics 

• Dimensions: 18.5 (W) x 6.25 (H) x 14.0 (D) 
• Weight: 12kg
• Year of release: 1979