Introduction: Stereo FM / AM Radio Receiver With VU Meter (TEA5711 + LM386)

By TeknoTrek
About: Welcome! As a hobbyist and technology enthusiast with a background in Electrical Engineering, the goal is to make complex electronics projects and DIY (do-it-yourself) activities accessible to everyone. This p…

In this project, I will show you how to build a high-quality Stereo FM / AM Radio Receiver using the TEA5711 radio IC, dual LM386 audio amplifiers, and a 10-LED stereo VU meter.

This radio is based on a personally tested and fully working prototype. It offers clear FM stereo reception, AM band support, adjustable tuning, volume control, and a real-time visual audio level indicator.

📺 Full Step-by-Step Build Video:

https://youtu.be/hSCuRKkPxRc

This project is suitable for:

  1. Electronics hobbyists
  2. DIY radio enthusiasts
  3. Students learning RF and audio circuits


Step 1: How the Radio Works (Block Overview)

The circuit is divided into four main functional sections:

  1. FM / AM Radio Receiver Module (TEA5711)
  2. Stereo Audio Amplifier (2× LM386)
  3. Stereo VU Meter Display (TA7666P / KIA7666P)
  4. Power Supply & Voltage Regulation

Each section is explained step by step in the following sections.

Step 2: FM / AM Radio Receiver Module (TEA5711)

The heart of this project is the TEA5711, a high-performance integrated FM stereo and AM receiver IC.

Key Features:

  1. Supports FM Stereo and AM in a single IC
  2. Operates at low supply voltage
  3. High sensitivity and stable reception

Important Components:

  1. Ceramic IF Filters (Y2, Y3 – 10.7 MHz):
  2. Ensure proper FM IF selectivity
  3. FM Antenna (AE1): Telescopic antenna input
  4. AM Antenna (L2): Ferrite rod antenna
  5. Variable Capacitor (C26): Manual tuning control
  6. Protection Diodes (D11, D12 – 1N4148):
  7. Protect antenna input from static discharge

This section handles all RF processing, mixing, IF amplification, and demodulation.

Step 3: Stereo Audio Amplifier (2× LM386)

The low-level audio output from the TEA5711 is amplified using two LM386 ICs, one for each channel.

Features:

  1. True stereo audio amplification
  2. Compact and efficient design

Important Details:

  1. Dual Potentiometer (RV2 – 50K):
  2. Controls volume for both left and right channels simultaneously
  3. Gain Boost Capacitor (C15 – 10µF):
  4. Increases LM386 gain to maximum
  5. Zobel Networks (R21/C19 and R27/C41):
  6. Prevent high-frequency oscillations and ensure stable output

This stage drives standard 8Ω speakers directly.

Step 4: Stereo VU Meter (TA7666P / KIA7666P)

This section adds a professional visual element to the radio.

Features:

  1. 10 LEDs total (5 per channel)
  2. Real-time audio level display

Technical Notes:

  1. TA7666P IC: Stereo level indicator
  2. Current Limiting Resistors (1.2K):
  3. Protect LEDs from overcurrent
  4. RC Networks (C5/R9 and C12/R13):
  5. Control response speed and sensitivity

The VU meter reacts smoothly to music and speech signals.

Step 5: Power Supply & Voltage Regulation

The radio operates from a 9V DC source (battery or external adapter).

Power Design:

  1. Input: 9V DC
  2. Regulated Output: ~5.6V for the radio section

Key Components:

  1. Zener Diode (D14 – 6V2)
  2. Transistor Regulator (Q1 – 2SC1402)
  3. Large Filter Capacitors (C1, C2):
  4. Reduce noise and ripple

This ensures stable operation and minimizes background hum.

Step 6: PCB Design and Layout

The PCB was designed specifically for low noise and easy assembly.

PCB Highlights:

  1. Wide GND traces to reduce interference
  2. Clear silkscreen labels for all components
  3. Optimized placement of:
  4. AM IF transformers
  5. Ferrite antenna
  6. RF-sensitive components

Control elements (Tuning, Volume, AM/FM switch) are aligned for easy access.

Step 7: PCB Production (Heat Transfer Method)

For DIY PCB manufacturing, mirror-image copper layouts are provided.

Tips:

  1. Print at 100% scale (1:1)
  2. Use mirror images for iron-on transfer
  3. Verify IC footprint alignment before etching

Incorrect scaling will prevent DIP ICs from fitting properly.

Attachments

Step 8: Assembly & Calibration Tips

  1. Solder low-profile components first
  2. Install RF components carefully
  3. Adjust AM IF transformers gently
  4. Keep antenna wiring short
  5. Follow the soldering order shown in the video

📺 Assembly Video:

https://youtu.be/hSCuRKkPxRc

Step 9: Final Result

Once assembled and powered:

  1. Clear FM stereo reception
  2. Stable AM reception
  3. Clean stereo audio output
  4. Smooth VU meter response

This project combines RF design, audio electronics, and visual feedback in a single build.

Step 10: More Projects

If you enjoyed this project, check out my other electronics builds:

🔹 DIY FM Radio with Arduino & Si4703

🔹 Powerful AM/FM Radio with CXA1019S

🔹 Arduino LC Meter

🔹 Home PCB Manufacturing Techniques

▶ YouTube Channel:

https://www.youtube.com/@TeknoTrek