Douk Audio Mini 6J1 Valve & Vacuum Tube Pre-Amplifier Stereo HiFi Buffer Preamp Notice:  Preamplifier needs to work with amplifiers or active devices;  Not PHONO preamp and can't be used for record players Classic 6J1 tubes with optimized circuit offer classic music experience Tube can be replaced by 61, 6AK5,6BC5, EF40, EF95, CV8505654; Much fun and high playability DC12V 1A universal power supply; Can be used in most countries and regions All aluminium alloy shell; Gold-plated terminals; ENIG PCB Dimensions: 98 * 100 * 32 mm / 3.86 * 3.94 * 1.26 in (without knobs and terminals) Power supply: DC12V 1A Frequency response: 20Hz (-0.2dB) ~ 20KHz (-0.2dB) SNR: 100dB Input sensitivity: 300mV ~ 2000mV Output: 3000mV THD: 1000mV 0.1% Weight: 350g / 0.77 lb It adopts the classic tube 6J1 to optimize the route. Replaceable design for you to upgrade it easily. The first amplifier using DC12V power supply which can be found easily. Applicable power supply specification: inner diameter: 2.1; outer diameter: 2.5