1、* With wide applied range and practicability, it can fit the majority of active speakers and power amplifiers in the market. 2、* The replaceable 6K4 vacuum tubes design can optimize the circuit. 3、* The audio part and the power part are completely separated, which minimizes the interference to the sound. 4、* The timbre is soft and beautiful, sweet and warm and with powerful bass, penetrating treble. 5、* With treble and bass adjustment, single power supply, it\u0027s small and portable, brings you much fun and conveniece. 6、* Using high-quality aluminum alloy housing with gold-plated connectors, it\u0027s durable and high-performance. Overview: With a wide applied range and practicability, this preamplifier can fit the majority of active speakers and power amplifiers in the market. The replaceable 6K4 vacuum tubes design can optimize the circuit. The audio part and the power part are completely separated, which minimizes the interference to the sound. The timbre is soft and beautiful, sweet and warm, and with powerful bass, penetrating treble. With treble and bass adjustment, single power supply, it's small and portable, brings you much fun and convenience. Using high-quality aluminum alloy housing with gold-plated connectors, it's durable and high-performance. Features: * With a wide applied range and practicability, it can fit the majority of active speakers and power amplifiers in the market. * The replaceable 6K4 vacuum tubes design can optimize the circuit. * The audio part and the power part are completely separated, which minimizes the interference to the sound. * The timbre is soft and beautiful, sweet and warm, and with powerful bass, penetrating treble. * With treble and bass adjustment, single power supply, it's small and portable, brings you much fun and convenience. * Using high-quality aluminum alloy housing with gold-plated connectors, it's durable and high-performance. Specifications: Model Number: TUBE-03 Tube Model: 6K4 Frequency Response: ±1.5(20Hz-20KHz) Audio Input Interface: RCA Audio Output Interface: RCA RCA Output: 0.9Vrms SNR: 100dB THD: 0.03% Treble Adjustable Range: ±6dB Bass Adjustable Range: ±10dB Input Voltage: AC 100-240V, 50/60Hz; DC 12V/1A Color: Black, Silver (Optional) Main Item Size: approx. 12 * 9.8 * 3.3cm / 4.72 * 3.85 * 1.29in Main Item Weight: approx. 318g / 11.21oz Package Size: approx.  22 * 21 * 7cm / 8.66 * 8.26 * 2.75in Package Weight: approx. 566g / 19.96oz Package List: 1 * Preamplifier 1 * Power Adapter 1 * User Manual (English & Chinese) 1 * Preamplifier 1 * Power Adapter 1 * User Manual (English & Chinese)