upc1892 chip design, with NE5532 pre-amplifier, there are treble, bass, balance, volume adjustment, potentiometer adjustment adopts DC control method, potentiometer separation will not cause interference, easy to use with single power supply    The pre-amplifier op amp chip uses a gold-plated IC seat, which is convenient to upgrade the more burnt op amp chip to improve the effect (basically, dual op amps can be used).    Working voltage: DC 12-24V or AC 8-16v  Board size: 100mm*50mm  Potentiometer spacing: 25mm (potentiometer fixed version)    Common problem handling: Current sound (interference): The tone board power supply must be powered by an independent transformer, the iron core type, the ring type and the R type are not good. (There is no good power supply, the effect. There is no way to talk about low noise). The potentiometer adjustment is out of control or the function is not normal: In this case, the potentiometer is mostly installed on the metal panel, which is short-circuited for some reason (1892 is DC controlled, the control voltage is short-circuited, and the function must be out of control). When encountering this kind of problem, it is necessary to remove all 4 potentiometers from the panel and test the machine, and find out the reason for the short circuit with the panel.