Moving Coil Head Pre-preamplifier

A special category of preamplifiers, they are the preamplifiers that undertake they amplification the low exit of Moving coil head, so that its drive to a input PHONO [RIAA] of preamplifier. With the moving coil heads, exist certain problems which it should we are careful in the designing of amplifier. The very low output level of head and the low output resistance, require a amplifier with very good behavior in the noise. In the circuit in order to we achieve, exist instead one transistor, four transistors connected parallel. This ensure the thermic noise distribution of transistors via four. In the circuit is used a type transistor [ BCY71 ], that it has very low noise characteristically. Resistors R1 and R2, ensure in the right adaptation with the head and it can be changed with other value so that it suits with the head, that we will use. For the circuit supply are used a 9V battery and a filter constituted from R9, C12, are ensured thus ` clean supply, exempted from noise.

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