Maximum Power Per Channel : NO POWERPackage : YesChannels : 2 (2.0)Certification : NONEModel Number : 6K4 tubeProduct description:This product is a tube pre-amplifier and needs to be connected to an active speaker or power amplifier. It cannot directly connect speakers and passive speakers, headphones, phono amplifiers, cars.Product name: tube preamplifierTube: 6K4/6A2/6J3(The tube is disassembled)Power supply: DC12-16V, current 1A or more (DC12V 1.5A supply power is recommended)(without supply power)Power socket: DC3.5/5.5*2.1Product support replace tube: 6J1 6J2 6J3 6J4 6J5 6A2 6K4 6K5 6AK5 6AU6 6BA6 6BD6 EF93 6K7 GE5654 etc.Pre-stage magnification: voltage magnification 5 timesPre-stage frequency response: 5HZ-500KHZPre-level sensitivity: 3VAudio input: low-level signal input such as mobile phone, CD, computer, TV, MP3, etc.Audio output: connect to power amplifier or active speakersSize: 87*75MMNote:The tube preamp is a class A amplification state.. It is recommended to use shielded wire for the signal wire. Common wires may cause leakage or noise. The high-fidelity lift can be adjusted freely, and the three-gear adjustment with a wave switch.The switch on the far left is Hi-FiThe switch is in the middle to raise aThe switch on the far right is the lift two. Note: 1. If the signal line is not shielded or the power supply is not well filtered, noise may be generated. It is recommended to use shielded wires and a clean power supply for testing. 2. The tube buffer is amplified by about 5 times. The pre-amp has an amplification function, which is connected between the audio source, the pre-amp and the power amplifier. The noise from the audio source is amplified, so please use a good audio source to test. Package included:1Pcs 6K4 /6A2Tube Preamp(optional)(without supply power)