Preamplifier circuit TL072 op amp based on the previously shared “NE5532 Preamplifier tone control” circuit is controlled according to the deeper and a little more powerful stereo two-channel preamplifier and solid bass, treble, balance, volume control. TL072 op amp... Electronics Projects, Tone Controlled Preamplifier Circuit TL072 Opamp "audio control circuits, " Date 2019/08/03