The circuit shown is an amplifier for medium impedance headphones including bass and treble control, and also balance to the stereo version. He was found in a publication of 1979, but can be mounted easily with the changes we made, using the most modern components. The circuit is powered by battery, but can be used power supply for greater autonomy. If source is used 9 V, it must have excellent filtering and a current of at least 200 mA. The tone control has bass and treble and two units with the balance control should be fitted for a stereo version. The input is high impedance and low impedance headphones can be connected at its output.
