Tag: Pre-Amplifier

Condenser microphone and dynamic microphone (moving coil microphone) has different characteristics. For dynamic mics, a biasing current is not needed because the transducer generate the electrical signal. In condenser mics, a bias current is needed to compensate the leakage in the microphone, and because of the pre-amplifier loading that discharge the condenser mic’s electrical charges. The microphone pre-amp described here […]

To produce a pre-amplifier with accurate RIAA response, this circuit use two stages of amplifier. This circuit is more complex than single op-amp RIAA pre-amp, but the performance is excellent in terms of accurate frequency response. Here is the schematic diagram of the circuit. The circuit uses LM833 high performance op-amp from National Semiconductor, giving the best performace of 0.1 […]

Recording Industry Association of Ameria (RIAA) has developed the recording standard of response curve for their recording. This curve is developed to optimize the gramophone recording response for lowest signal-to-noise ratio for gramophone technology. Because the tape recording response is not linear, the pre-amp for gramophone playback pickup should have such  response that restore the original response, a flat response […]

Here is a schematic diagram of electret microphone pre-amplifier using LMV721 op-amp. because the LMV721 has low noise and low power features, it would be an ideal choice for  battery powered microphone preamplifier. The LMV721 is connected as an inverting amplifier. Resistors, R1 =R2 = 4.7k, sets the reference at mid point between VCC = 3V and ground. Thus, this […]

Balanced input has three connections, ground, positive signal, and negative signal. When we trace the signal using oscilloscope, if we take the ground as the reference, then the negative signal and the positive signal has similar shape but with inverted polarity. If we measure the signal between positive and negative output, the we have two times larger signal than what […]