Features T4 PLUS tube preamp meets more HiFi audio needs: MM /MC phono input, support multiple input impedance switch (1K/470/220/100/47/22/10), converts phono signal to line level signal, low-noise integrated circuits and high-quality components to ensure clear sound. 3.5mm AUX input, amplify the low level audio signal from your phone, tablet, PC, MP3 etc., easier to drive amplifier or active speaker and greatly improve the sound quality. Unique and amazing combination in the appearance: integrated T4 PLUS preamp with retro tubes and VU meter into a whole, the pointer dancing in the warm light with strong vintage feelings when enjoy HiFi music, dynamically decorates the audio system and give you a different acoustic enjoyment with large dynamic and sweet tube sound even in limited space. Imported JAN5654 tubes and vintage warm sound: default comes with JAN5654 tubes, improves everything associated with your music such as detail, transparency, immediacy, richness, dynamic, tone etc., much better than 6J1 series especially in human voice. Pluggable tube socket for tube rolling and sound-shaping, easy to pick from and alter the sound signature to ones preference. 3.5mm headphone output and perfect circuit design: T4 PLUS also with built-in classic headphone amp circuit (2*NE5532), easily to drive 32-300 ohm headphones. Reasonable and advanced architecture, TI TPS5430+7205MOS for power management, TL071+JRC2068 phono preamp circuit etc., enjoy HiFi analog sound and first-class design with an unbeatable low cost. Mini size and excellent performance: all designs full of details, such as solid aluminum alloy knob, gold-plated terminals, grey integrated moulding aluminum alloy shell decorates with built-in VU meter, looks vintage and elegant. Not only a MM/MC phono preamp, but also a stereo audio preamp and headphone amplifier, especially designed for the audiophiles who pursue HiFi sound. Warm tips: 1. 3.5mm AUX input with priority, please make sure the AUX cable has been pulled out if want to use MM/MC phono input. 2. Stereo RCA and 3.5mm headphone jack can output at the same time, and the knob also controls the volume of two outputs simultaneously. Parameters Brand: Douk Audio Model: T4 PLUS Audio input: MM phono/turntable / 3.5mm AUX Audio output: stereo L/R RCA / 3.5mm headphone jack Max output power of headphone jack: 150mW@32 Matched headphone impedance: 32-300 AUX IN