An application, which is considered, of very good quality sound since the entrance transistors are working at Class A. The quality of sound depends to a large extent on IC1, which must be of good quality. It can be chosen from several IC with the best from the point of cost efficiency the proposed NE 5534 (NE 5532 for stereo construction) and the series TL071 (TL072) for greater input impedance. This particular application can be used with very good results and as driver headphone with higher 47R impedance. The amplification can be changed and adapted to the amount we want, if changing the feedback resistors R6/R7.