<html><body><div style="color:#000; background-color:#fff; font-family:bookman old style, new york, times, serif;font-size:12pt"><div><span>Also try wrapping the supply line around a ferrite core. This should smooth some of it out.</span></div><div></div><div> </div><div>~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~<br>C. Mike Rice<br><br></div> <div style="font-family: 'bookman old style', 'new york', times, serif; font-size: 12pt;"> <div style="font-family: 'times new roman', 'new york', times, serif; font-size: 12pt;"> <div dir="ltr"> <hr size="1"> <font size="2" face="Arial"> <b><span style="font-weight:bold;">From:</span></b> Mitch Patenaude<br> </font> </div> <div class="y_msg_container"><br><div id="yiv2424073440"><div dir="ltr">Analog is much trickier and more finicky than digital electronics.<div><br></div><div style="">One problem is that you might be creating a ground loop by connecting the ground (common) both at the IO pins and audio in. You
might try removing the ground from one of those, or powering the amp some other way entirely (at least as a test.)</div>
<div style=""><br></div><div style="">As Frank suggested, a cap on the power line may help with some of the ripple that may be coming through. If you have an oscilloscope, you can check the power pin for ripple.</div><div style="">
<br></div><div style=""> -- Mitch</div></div><div class="yiv2424073440gmail_extra"><br><br><div class="yiv2424073440gmail_quote">On Thu, May 30, 2013 at 12:30 PM, jezra <span dir="ltr"><<a rel="nofollow" ymailto="mailto:jezra@jezra.net" target="_blank" href="mailto:jezra@jezra.net">jezra@jezra.net</a>></span> wrote:<br>
<blockquote class="yiv2424073440gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex;">In my current computer project, I have a small audio amplifier<br>
connected to a small SBC (Single Board Computer), and the amp is also<br>
getting power from IO pins on the SBC. When everything is powered up,<br>
there is a lot of staticy background noise coming from the amp, and I<br>
was wondering if anyone had a suggestion for ways to reduce the noise?<br>
<br>
<br>
Jezra<br></blockquote></div></div></div><br></div> </div> </div> </div></body></html>