Tech Forum

I would try using either one or two LM386s in low gain low noise configuration, depending on if you're using mono or stereo headphones. Look at the Data Sheets at: www.nari.ee.ethz.ch/wireless/education/PPS/PPS02/doc/LM386.pdf and page down to page 5. The very first schematic is for the amp used without the 10µf cap between pins 8 & 1 which limit the gain to 20 & the noise is greatly reduced as well.

Also, I noticed that Russell Kincaid had a similar question in the same issue, page 24 and his answer was given in Figure 7, which seems to be missing from my paper magazine, perhaps he'd be kind enough to send it to you directly? (Ed: Figure 7 can be downloaded from the link on this page {filedir_8}index.php?/magazine/article/august2012)

I also found a link to a solution (with a problem of high hissing noise) for the same application on-line at: www.edaboard.com/thread232457.html  He ended up saying "Now I am able to reduce the hiss type noise at the output by just removing the 10mf cap between pins 1 and 8. There is still a little bit of hiss noise at the output but for me that is ok." Which is then the configuration I mentioned above in the Data Sheets.

A LM386 based circuit would be simple and will run from a 9V battery. See http://web.mit.edu/6.s28/www/schematics/lm386.htm

You can also buy a small kit such as at www.electronics123.com/kits-and-modules/audio-amplifier-1W-LM386-kit.html

If the output sounds to harsh, drop the gain by removing the feedback cap (C1 in the diagram at the first link).