This product uses 6j1 tube to do -level lm1875 amplifier, with amp function. After 6j1 tube buffer, can significantly reduce the "digital " and "transistor sound", so that the whole sound system to bring a natural ", the sound is more , soft. Than the average lm3886, tda7294 better listen. The -level is the use of 6J1 fever tube gall bladder the : imitation machine music fax X-10D circuit principle design, to be reasonable to optimize, more stable than the original machine performance, the tube to play increased by 10 percent. This machine uses dual AC 18v input, do not have to worry about looking for high voltage power supply The board comes with boost to enjoy you in the low power supply to enjoy the charm of high-voltage tube Power works: a power supply, tube filament began to heat, then boost from the voltage began to boost, and other tube filament hot, the boost is just boost finished, so this is the same with the rectification, 4 470UF The capacitor filter is very clean, power supply system will not have the exchange of sound, the filament is DC 12V power supply, the need for two tube filament is in series, the use of DC filament is also to reduce noise. the output level automatically switch to the headset or the rear lm1875 amplifier, that is, after inserting the headset, the amplifier without output, do not insert the headset, is to the amplifier output The output of the sound slightly smaller than the digital , thrust in general, if the can accept this way, also the output of the product, Then you can try, after this product processing, headset sound there will be a kind of and delicate "." Headphone output function can also be used to do the output level, then the other after the amplifier. Color: n material: metal After the lm1875t amplifier: Europe and the LM1875T classic design Wiring is reasonable Outstanding performance Have sought by DIY lovers to retain all the original alignment, to retain the original performance of the premise, also to strengthen the original components of the Oh, the introduction of 6j1 tube to the sound more and beautiful Power supply voltage: the default dual AC 18v / current 3A, power 60w or more (the maximum voltage can not the dual AC 19V, nor less than 18v, otherwise the tube is not , the sound distortion. If you need to use AC 12v, need to the wire resistor For 2.2 Europe, then the amplifier output power will be slightly lower) Amp / front output: magnification about 0.8 (amp function can try to use, you can the high sensitivity of the headset, thrust in general, the amp output can also be used to the current level of function, the output then drive the other amplifier, with tube . ) Lm1875t amplifier output power: typical 20W (maximum 30W) Speaker impedance: 4-8 Harmonic Distortion: Less than 0.04% Signal to noise : 105dB Frequency response: 14Hz-100kHz (by the RC high and low circuit count the maximum range of 3.29Hz-482.29kHz) Package Contents:1 x lm1875t power amplifier board kit Only the above package content, other are not included. Note: Light and different displays may cause the color of the item in the a little different from the real thing. The measurement allowed error is +/- 1-3cm.