BGW-150 power amplifier circuit

The BGW150 power amplifier is a two-channel power amplifier produced by the American BGW Company in its early stages. It is the youngest brother in the BGW family . Its output power is not large (75W×2), but it has great sound and is highly praised and loved by audiophiles. The circuit
is shown in Figure 6-23. The reason is that the power amplifier circuit design is unique and breaks through the tradition. Concept q First of all, the circuit input stage of the IX;w150 power amplifier uses the NE5534,
which is known as the "King of Op Amp" . Today, NE515 34 can be found everywhere, but more than ten years ago. The designer of BGW150 has a unique vision to use NE5534, which can not but be said to be a wise move. What is even more valuable is that when using the NE5534, this machine cleverly made some "hands and feet" on the power supply to make the NE5534 play more vividly.     Usually the output terminal ⑥ of the NE5534 is ov, and Ⅸ) W-150 power amplifier Unconventional; the positive voltage at pin ⑦ of the power supply is 10.7V, the negative power supply voltage at pin ④ is 1 loV, and the positive and negative voltage difference at the port is o. 7V. In this way, the output pin 6 is no longer ov, but 0.3V. Its purpose is to force the internal output stage of the op amp to work in a Class A state, so that the output tube always has current flowing through it. This significantly improves the op amp. The inherent defects caused by the transient characteristics and quasi-complementary output form, such as switching distortion, crossover distortion, etc., make the sound quality clearer, more delicate, transparent and natural.     From the internal circuit structure of NE5534 , it can be seen that its final output part is a quasi-complementary form output, which is the same as the dual op amp NE5S 35 (NE5535's secondary output is in a quasi-complementary form), so it is a bit prouder in terms of power supply . There is a certain basis and reason for using the hands and feet to engage in massage .