BTJ tone control circuit transistor (BC547) based on mono, stereo preamplifier PCB drawings are also made ​​with solid is in addition TDA2030A Application, 2x15W there. The only source on the operating voltage of the control circuit 12v DC 18v... Electronics Projects, Transistor Tone Control Circuit and TDA2030 Amplifier "audio control circuits, " Date 2019/08/03