1. Using 6J5 tube NE5532 2. The main filter capacitor uses the 470UF/25V and the coupling capacitor uses the imported capacitor 1UF. 3. The resistor uses high-precision chip resistor to ensure a good signal-to-noise ratio of the whole machine. 4. PCB adopts 1.6mm thick double-sided sheet 2.0 oz copper thickness and tin-spraying process to ensure good passing performance of large and small currents. First-class PCB quality. 5. The input and output are made of gold-plated RCA lotus seat which is durable and beautiful! The board layout is reasonable beautiful and the current is small. Basic parameters: Power supply: DC12V2A needs to be regulated by 12V not higher than 12V Machine size: about 129* 100* 35MM without tube height Panel function: switch treble adjustment bass adjustment total volume Note: 1. This finished machine is a preamplifier not an amplifier. It should be used with a post-amplifier or an active speaker. It is not allowed to directly connect passive speakers speakers and earphones to the power amplifier; if it is not used the car will be burnt if the voltage is unstable. 2. The probability that the normal audio line or power supply is not good enough to cause the noise at the bottom noise is very high. It is recommended to use a good audio cable or power supply. 3. Make sure that there is no problem with your source. The preamplifier itself has a preamplifier function. If the source itself is noisy then the preamplifier will only amplify its noise. Please use a good source test. 4. Check if the tube is plugged into the base. Please insert the tube and the base. Be sure to insert the tube in case of power failure. Note: Power supply is not included in the package. You need to buy 12V2A power supply by yourself. Material:Aluminum alloy colour:Silver Package Contents: 1 * 6J5 Tube Preamplifier Only the above package content other products are not included. Note: Light shooting and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm. About Us We provide the good product with the best pricewe support Wholesale/Drop Shipping Order 1. For Drop Shipping order please remark"dropshipping order" we will prioritize it. 2. For Wholesale/Drop Shipping orders if you have any ideas about the price or packageplease contact us in advancewe will give you the best service to satisfy your demands. About Shipments 1.We will send out the orders ASAP once your payment is completed normally. 2.Please write your complete delivery address with correct phone number and zip code especially please confirm your full name. About After-sale Service We are reliable seller and we have our professional after-sale service for all of our customers. If there is any question about the orderplease contact us in advance we will always here until you get a happy answer. About Feedback 1. Please check the package and item when you get carefully to make sure there is no problem. 2. If you have any problem or are not entirely satisfied with your packageplease don’t be hesitate to contact us first before leaving negative feedback. We will resolve the problem to satisfy you. 3. If there is no problem please leave us five star positive feedback. Your affirmation is our greatest motivation ! ! !