The main problem with the design of stereo amplifier with a total bass driver, is that the signals of left and right channels, sooner or later, are summarized. As a result of merely adding up, the separation between channels is reduced to a minimum and violated the very idea stereofonii. The most efficient method of summation, known today - signal active smesitelyami - filters with high input impedance, which is often used by field-effect transistors. Subsequent cascades enhance increase the amplitude of the signal. I tried to make some other way - most to weaken the signals of channels and to make their addition, as late as possible, before entering signal with high sensitivity (TDA 7240 - 46dB). The second chip-TDA 1517, serves as a mid-frequency driver. I must say that the problem is not solved completely, the separation between channels is desirable to do more, subjective listening showed a contraction of panoramas, lack of air, which is inherent in amplifiers with independent channels. Listen to music using the device somewhat tiresome, but it very effectively transmits audio material of films and computer games. In any case, the amplifier has shown significant superiority over the multimedia system Logitech Z - 340, which is one of my friends recently bought for $ 60. Another nice time - managed to realize the possibility of simultaneous volume in all channels, which will agree, very convenient. Thus, the scheme was recommended for the recurrence of 2.1 Channel Systems, with the prospect of it improving.