Simple and low cost. The optimal supply voltage is around 50V,
but this amp work from 30 to 60V. The maximal input voltage is around 0.8 - 1V.
As you can see, in this design the components have a big tolerance, so you can
build it almost of the components, which you find at home. The and transistors
can be any NPN type power transistor, but do not use Darlington types... The
output power is around 60W.
Some comments:
- capacitor C1 regulates the low frequencies (bass), as the capacitance
grows, the low frequncies are getting louder.
- capacitor C2 regulates the higher frequencies (treble), as the capacitance
grows, the higher frequencies are getting quiter.
- this is a class B amplifier, this means, that a current must flow through the
end transistors, even if there is no signal on the input. This current can be
regulated with the 500Ω trimmer resistor. As this current incrases, the sound of
the amplifier gets better, but the end transistors are more heating. But if this
current decrases, the transistors are not heating so much, but the sound gets
worse...
author: Jacint Chapo
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