Why A Audio Attenuator:
If you are into ESSB audio, or your just using some type of outboard audio equipment you may need a attenuator so that you do not over drive the front end of your transceiver. This attenuator is used to set down the audio going into  your radio by about 23db. I could have bought one. I decide to build my. And beside I like the idea of building so of my own gear and having some of the parts in my junk box it all work out. I built two of these attenuator but each one was a little different. The first one I built was a little more involve with more parts. The two one I built was very simple and only require a few parts that you may fine in your parts box. I will start with the simpler one first. Both of these attenuator were design by W2IHY Julius. These audio attenuator seem to have two name's for them. One being a Ibox and the other Murf Box.

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Second Attenuator I Built:
Parts needed for this project.
Resistors R1 2.2k -  R2 10k - R3 820 ohm.
2 1/4 phone plug. Or you can use RCA plugs if you like.
1 Audio transformer Stancor TTPC-2 or TTPC-8 telephone coupling transformer from Allied Electronic
1 Plastic or metal enclosure box. I use a small plastic box from Radio Shack.
As you can see from the picture of Fig 1 there is not much to this unit at all. Very easy to build. Fig 2 is a picture of the
schematic. This was my first attempt using a program to draw this schematic.
Fig 1
R2 can be replace with a variable 10k or 100k resistor if you like. I used a fix resistor in mine and works great. All resistor are 1/4 watt.

Click image to view the Finish Product...