Magnetic Phono Cartridges Transistor RIAA Preamp

The following two-transistor circuit is a preamplifier for magnetic phono cartridges, characterized by its frequency response defined by the RIAA standard for phono recording. This preamp circuit has a gain of approximately 40 dB (midband) at 1 kHz. The circuit utilizes an LM381/1A and includes RIAA equalization, ensuring ultra-low noise performance. The DC voltage level at the output of this circuit is about 16.5V. This simple circuit serves as a magnetic pickup phono preamplifier, providing proper loading for a reluctance. The gain is approximately 25 dB at 1 kHz (2.2mV input for 100mV output). This circuit is efficient for inexpensive moving-magnet cartridges and can be used to listen to well-preserved old vinyl records in conjunction with audio power amplifiers.

The described circuit is designed as a preamplifier specifically for magnetic phono cartridges, which are common in vinyl record playback systems. The use of two transistors allows for effective amplification of the low-level signals generated by the phono cartridge, which typically produce output voltages in the millivolt range. The gain of around 40 dB at midband frequencies, particularly at 1 kHz, ensures that the output signal is sufficiently amplified for further processing by audio power amplifiers.

The integration of the LM381/1A operational amplifier provides a solid foundation for the circuit, known for its low noise characteristics, which is critical in audio applications to prevent unwanted interference from being amplified alongside the desired audio signal. The inclusion of RIAA equalization is essential for phono preamplifiers, as it compensates for the frequency response curve of vinyl records, which are recorded with specific equalization to optimize sound quality and minimize surface noise.

The output voltage level of approximately 16.5V allows for compatibility with standard audio equipment, ensuring that the signal can be effectively processed without distortion. The circuit's ability to provide proper loading for the magnetic cartridge enhances audio fidelity, making it suitable for playback of vintage vinyl records. This design is particularly advantageous for users with inexpensive moving-magnet cartridges, as it offers a cost-effective solution for high-quality audio reproduction.

Overall, this preamplifier circuit serves as an efficient and effective means of amplifying the output from magnetic phono cartridges, ensuring that users can enjoy the rich sound quality of their vinyl collections.The following two-transistor circuit is a pre-amplifier circuit for magnetic phono cartridge, which is characterized by its frequency response defined by RIAA standard for phono recording. This pre amp circuit has gain around 40 dB (midband) at 1 kHz. Here is the schematic diagram of the circuit: This circuit is a ultra low noise magnetic phono pr eamp. This circuit uses an LM381/1A. This circuit also includes RIAA equalization. This circuit has ultra low noise. The DC voltage level at the output of this circuit is about 16. 5V, Continue reading †’. This is a simple circuit of magnetic pickup phono preamplifier. A proper loading to a reluctance is provided by this circuit. Here is the circuit: The gain provided by this circuit is approximately 25dB at 1kHz (2. 2mV input for 100mV Continue reading †’. This circuit is a simple circuit that can be used to listening old vinyl discs from a well preserved collection. This circuit efficient for cheap moving-magnet cartridges. It can be used in connection with the audio power amplifiers shown in Continue reading †’. 🔗 External reference