Dilshan R Jayakody’s Web Log

This project is about a single-channel microphone echo generator circuit. This circuit builds around the Holtek HT8970 echo effect generator IC. It offers complete control of the echo effect by providing delay, mix, and output level adjustments.  HT8970 is an echo/surround sound effect generator IC with 20Kb SRAM. It also contains the built-in VCO stage, AD, and DA converters. The chip costs less than 0.5 US$ and is commonly available in the market. Prototype build of the echo effect generator circuit. The given schematic offers a maximum of 320ms time delay and works with a single-rail 9V DC power supply.  In addition to the HT8970 integrated circuit, this circuit uses an NJM4558 op-amp to amplify the input and output audio signals. HT7150 voltage regulator uses in this design to power up the HT8970 IC. The HT7150 is a low-power 5V regulator IC from Holtek, the same maker of the HT8970 IC. Top view of the prototype build. The circuit designs to work with 500Ω dynamic mic...

This is an easy to build high quality echo sound generator and it’s completely based on Princeton Technology’s PT2399 echo sound IC. This supplied circuit is specifically design to interface with electronic musical instruments (e.g: electronic audio synthesizers, electronic organs, etc.) and with microphone systems. This echo sound effect generator requires 12V - 25V DC power supply and it can deliver aprox. 20W output power (with 8 Ω speaker and 20V - 5A DC power supply). This given design of echo sound generator has 3 main controls, such as echo delay adjustment, echo-effect mixer and master volume control. This delay and mixing ratio is heavily depended on input source. Output of C1 note with maximum and minimum echo effects At the testing stage we test this system with lot of input sources. According to our experiments this system can product good results with slow speed music and it produce excellent results with the voices. When it comes to high speed music (with ma...