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Very simple 9V Battery operated head amplifier to be used with Moving Coil Cartridges.
The circuit was designed for a collector current of approximately 2 mA per transistor, meaning each channel will consume 8 mA, or 16 mA for a stereo amplifier, If we add a LED to indicate that the unit is on, we will consume another 12 mA, so the entire preamplifier will consume about 30mA.
It is important to remember that a 9-volt alkaline battery has a capacity of between 400 and 600 mAh when discharged at very low currents (around 10 mA). A 9-volt battery was selected as the power source for this design for two reasons:
1. Simplicity,.
2. It produces practically no noise.
Both the version made around NPN and PNP transistors are shown.
For the NPN version, use BC550C transistors
For the PNP version, use BC560C transistors
It is recommended to use resistors with a tolerance of 1%
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