SR wrote:
I would like to improve the audio in my shortwave receiver. I would
like to find a device that I could plug into the headphone hole in the
radio and my headphone to the device.

The type of device I am looking for should have filters and work in SSB.
To help cut down on static, radio and noise. And if it has a tone &
tuning button that will be good too.

How does this work and what could I use?

SR!

Assuming you are looking to clean up voice comms and not music look for
a used Daiwa AF606K audio filter - one of the best performing analog
units I've used. Also look for a used Datong FL3. Finally, MFJ had
made and I presume they still make some decent analog audio filters.


Here's a link to some end user reviews of several digital and analog
audio filters. http://www.eham.net/reviews/products/6