Audio Compressor

This simple compressor is designed to prevent large sudden changes in the loudness of an audio signal.

D1, D2, D3: HEP154 or SK3311 or NTE116. Diodes having similar characteristics include 1N321, 1N503, 1N504, 1N1008, 1N1028.

Q1: HEP243, SK3512, or NTE128 (Si NPN, max I_C 1 A, BV_CBO 120, BV_CEO 80). Other transistors with similar characteristics include 2SC97, 2SC108, 2N497, 2N498, 2N656, 2N2192, 2N2193, 2N2890, 2N4943.

We haven't tested this circuit; it was passed along by a friend. If you try it, please let us know what results you get.

Other compressor/limiter schematics on the web:
members.aol.com/jorman/ssm2166.htm
www.eklektix.com/gfc/elect/microfm/fmlimiter.gif
If you go to Google or another good search engine and enter the phrase audio compressor schematic you will find other circuits to study.

 
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