Audio Hiss in simple microphone circuit, Need tips on reducing from someone who has done it before

Thread Starter


Joined Mar 5, 2016

We are building a fairly simple circuit to take a 4-6 Ohm aviation microphone and amplify it to a military headset. We are CLOSE, but there is a small amount of "hissy white noise" in the circuit that we are trying to get out.

Is there anyone on this forum who has conquered a similar problem?


Joined Nov 30, 2010
I would guess, "yes". Probably half of us.
The first problem is that we can't guess what circuit you are trying to use. How about a drawing of the circuit?


Joined Nov 30, 2010
The main source of a Hiss in low signal amplifiers is Thermal noise
That is the puzzle here. With a source impedance around 5 ohms, that circuit should be a slam-dunk. I hope the Original Poster wasn't a, "drive by" who will never be heard from again.:(


Joined Aug 1, 2013
No clue, but probably not as good. It strength is using an 8-ohm speaker as a current source, turning the low impedance into an advantage. In that application it is better than a traditional voltage preamp.