Buffer HiFi 6J5 Bluetooth 42 Tube Preamp Amplifier Stereo Preamplifier with Treble Bass Tone Ajustment(Silver) DY 1. Using 6J5 tube, NE5532_x000D_ 2. The main filter capacitor uses the 470UF/25V, and the coupling capacitor uses the imported capacitor 1UF._x000D_ 3. The resistor uses high-precision chip resistor to ensure a good signal-to-noise ratio of the whole machine._x000D_ 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._x000D_ 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._x000D_ Basic parameters:_x000D_ Power supply: DC12V2A ( needs to be regulated by 12V, not higher than 12V)_x000D_ Machine size: about 129* 100* 35MM (without tube height)_x000D_ Panel function: switch treble adjustment bass adjustment total volume_x000D_ Note:_x000D_ 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._x000D_ 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._x000D_ 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._x000D_ 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._x000D_ Note:_x000D_ Power supply is not included in the package. You need to buy 12V2A power supply by yourself._x000D_ Material:Aluminum alloy_x000D_ colour:Silver_x000D_ Package Contents:_x000D_ 1 * 6J5 Tube Preamplifier_x000D_ Only the above package content, other products are not included._x000D_ 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. _x000D_ _x000D_ _x000D_ _x000D_ _x000D_ _x000D_ _x000D_