Power Amplifier OCL 300W HIFI by transister

Source :: http://users.otenet.gr/~athsam/power_amp_300w.htm

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For many application there’s no substitute for sheer power- low efficiency speakers, outdoor sound systems, or maybe you like the full flavour of the dynamic range of a high power amp. Whatever your requirement-this super power module should fit the bill. How it works: The amplifier can be divided into three separate parts. These are : the input stage, which consists of Q1-Q9 , a high gain, low power driver; the output or power stage- witch only has a voltage gain of four but enormous power gain; and the power supply. The input stage is a complementary -differential network, each ‘’side” with its own current source. Each transistor in this stage is run at a collector currant of about 0.7mA. Emitter resistors are employed to stabilize the gain and improve linearity. The output of Q1-Q5 drives Q7 and Q9. The latter are virtually two constant-current sources run about 7mA collector current. With an input signal these ”current” sources are modulated out of phase - the collector current of one decreases while the other increases.

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