Anyone who has played around with repeaters very much has likely run into the problem of tapping into an audio source from a repeater or linking radio which turned out to still have the preemphasis which is used in FM audio transmission. This simple little audio
deemphasis filter circuit will flatten the audio, removing the preemphasis curve and yielding audio that is suitable for feeding to the input of another device. Get rid of that “tinny” sound and make your setup sound much, much better. This easy to build circuit will eliminates the double preemphasis which occurs when tapping discriminator audio out of one repeater and feeding it straight into a linking radio or repeater which adds preemphasis again. Play around with the capacitor value a bit if you want to custom-tailor your audio even further for a nice, clean, natural sound at the other end of the system.