Hey Fons,<br><br>How can I check if the keyboard/power supply is grounded? The power supply itself is a three pronged one....<br><br>Thanks.<br><br>Andrew.<br><br><div class="gmail_quote">On Sun, Nov 29, 2009 at 3:55 PM,  <span dir="ltr">&lt;<a href="mailto:fons@kokkinizita.net">fons@kokkinizita.net</a>&gt;</span> wrote:<br>
<blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;"><div class="im">On Sun, Nov 29, 2009 at 03:16:33PM +0000, Andrew C wrote:<br>
<br>
&gt; I&#39;m just wondering, is the start of this short recording a ground hum<br>
&gt; loop? It appears to be a weird high pitched whine in there as well...<br>
<br>
</div>325.3 Hz and harmonics, either from digital circuits in your<br>
keyboard, or from a switching power supply.<br>
<br>
Is the keyboard itself grounded ? If not try that first (if<br>
it has a ground pin...)<br>
<div class="im"><br>
&gt; Could a DI box solve this problem?<br>
<br>
</div>One that provides ground separation (i.e. with<br>
a transformer) probably will.<br>
<br>
Ciao,<br>
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--<br>
FA<br>
<br>
Io lo dico sempre: l&#39;Italia è troppo stretta e lunga.<br>
<br>
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