Voice Echo

Rajkumar Sharma      http://www.rajkumarsharma.com  
Project tested


This project is a Voice echo module with build-in amplifier and on-board mic.


A project has been designed around Holteks Ht8970 voice echo IC.  Project can be used in various audio systems karaoke, toys, animatronics, show, display, exhibitions, and sound equipment’s.

The HT8970 is an echo/surround effect processor. It is designed for various audio systems including karaoke, television, sound equipment’s, etc. The chip consists of a built-in pre-amplifier, VCO or Voltage Control OSC, 20Kb SRAM, A/D and D/A converters as well as delay time control logic.


  • Supply Input 5V DC
  • Onboard MIKE and Aux audio input
  • MIKE and Aux and selection via jumper
  • Input/MIKE signal level adjustable via preset
  • It can work in two modes – echo or surround
  • Output signal level adjust via preset
  • Onboard preset for sound delay
  • Onboard LED for power supply indicator
  • Four mounting holes of 3.2 mm
  • PCB dimensions 79 mm x 70 mm


Parts List



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