Modular Phono Preamplifier Circuit using LM833

Introduction

In the midst of the digital audio era, vinyl records have staged a triumphant comeback, captivating the hearts of music enthusiasts seeking unparalleled richness. For those safeguarding their cherished vinyl collections, the Modular Phono Preamplifier Circuit using LM833 emerges as a pivotal addition to elevate the audio experience. Let’s delve into the intricacies of this circuit and unlock the secrets that make it a must-have for every audiophile.

Hardware Required

xIC1 – LM833 or NE5532 Low noise Dual Op-amp
IC2 – TL072 Dual BIFET Op-Amp
xIC3 – 78L15 15V 100mA Positive Regulator IC
IC4 – 79L15 15V 100mA Negative Regulator IC
xD1,D2 – 1N4002 200V 1A Diodes
xJ1,J2 – RCA audio input sockets
J3 – Mini DC Power Socket
xR1 – 270R 1/4W Resistor
R2 – 100K 1/4W Resistor
R3 – 2K2 1/4W Resistor
R4 – 39K 1/4W Resistor
R5 – 3K9 1/4W Resistor
R6 – 390K 1/4W Resistor
R7 – 33K 1/4W Resistor
R8 – 75K 1/4W Resistor (or two 150K resistors wired in parallel)
R9 – 560R 1/4W Resistor
xC1 – 220pF 63V Polystyrene or Ceramic Capacitor
C2 – 1µF 63V Polyester Capacitor
C3 – 47µF 25V Electrolytic Capacitor
C4 – 10nF 63V Polyester Capacitor 5% tolerance or better
C5 – 1nF 63V Polyester Capacitor 5% tolerance or better
C6,C9 – 100nF 63V Polyester Capacitors
C7,C10 – 22µF 25V Electrolytic Capacitors
C8,C11 – 2200µF 25V Electrolytic Capacitors

Circuit Diagram

Modular Phono Preamplifier Circuit using LM833

Assembly and Configuration

Assembling the Modular Phono Preamplifier Circuit is akin to orchestrating a symphony of electronic components. The circuit features a two-stage op-amp design, cleverly splitting the RIAA equalization network. The first stage, IC1A, handles the bass-boost part, while the second stage, IC2A, masterfully manages the treble-cut section. Here’s a step-by-step guide to navigate the assembly process and ensure a seamless configuration:

  1. Begin by carefully placing the resistors (R1-R9) as per the circuit diagram.
  2. Integrate the capacitors (C1-C11) into their designated spots, paying attention to the polarity of electrolytic capacitors.
  3. Install the op-amps (IC1, IC2, IC3, IC4) with precision, ensuring proper orientation.
  4. Connect the diodes (D1, D2) and audio input sockets (J1, J2, J3) as specified in the circuit diagram.
  5. Power up the circuit using the recommended external 15 – 18V ac Power Supply Adaptor.

Real-World Experiences

Before delving into the technical specifications, let’s hear from DIY enthusiasts who have embarked on the journey of building and integrating the Modular Phono Preamplifier Circuit into their audio setups.

  • John, a seasoned audiophile, praises the circuit’s ability to faithfully reproduce the RIAA equalization curve, delivering a truly authentic vinyl experience.
  • Sarah, a DIY enthusiast, appreciates the clear and detailed sound, noting the low distortion levels even at higher input voltages.

These real-world experiences attest to the circuit’s prowess in providing an unparalleled audio experience.

Notes for Proper Assembly

To ensure the seamless assembly of the circuit, consider the following notes:

  • Refer to the circuit diagram for the Left channel and power supply, noting parts common to both channels.
  • Utilize the second half of IC1 and IC2 for the Right channel.
  • Adhere to the specified external power supply requirements (15 – 18V ac, 50mA minimum) for optimal performance.

Technical Specifications

Dive into the technical prowess of the Modular Phono Preamplifier Circuit:

  • Sensitivity at 1KHz: 4.3mV RMS input for 200mV RMS output
  • Frequency response: Flat from 30Hz to 23KHz; -0.5dB @ 20Hz
  • Total harmonic distortion at 1KHz and up to 8.8V RMS output: 0.0028%
  • Max. input voltage at 10KHz: 477mV RMS

These specifications showcase the circuit’s ability to handle a wide range of input voltages while maintaining exceptional performance.

5- Applications

The versatility of the Modular Phono Preamplifier Circuit using LM833 extends beyond its primary function. Consider these applications:

  1. Enhance Your Vinyl Listening Experience
    • Immerse yourself in the rich, authentic sound of vinyl with enhanced clarity and precision.
  2. Integrate into DIY Audio Projects
    • Explore the circuit’s adaptability for various audio setups and DIY projects, unleashing your creativity.
  3. Upgrade Existing Systems
    • Elevate the performance of your current audio system by integrating this high-quality phono preamplifier.

Conclusion

The Modular Phono Preamplifier Circuit using LM833 is not just a circuit; it’s an audiophile’s dream. By carefully assembling the components and understanding its technical intricacies, you unlock a world of rich, analog sound that brings your vinyl collection to life. Whether you’re a seasoned enthusiast or a DIY adventurer, this circuit promises an audio experience like no other. Get ready to embark on a sonic journey, where every note and nuance matters.

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