HiFi Vacuum Tube Preamp Stereo 4-way Audio Switcher Box Desktop Headphone Amp. 1 Tube Preamp Black. Headphone output impedance: 32-300Ω. Headphone max power: 160mW/32Ω. Default Soviet Union 6H3N tube, can be replaced by Beijing 6N3 / Soviet Union 6H3N-E etc.
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