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<DIV><FONT face=Arial size=2>Hi all !</FONT></DIV>
<DIV> </DIV>
<DIV><FONT face=Arial size=2>at last I have managed to built my own TR909 - bass
drum pcb. It works prettty well (see <A
href="http://www.analog-synth.de/synths/tr909/tr909.htm">http://www.analog-synth.de/synths/tr909/tr909.htm</A> for
details), but I found one problem :</FONT></DIV>
<DIV><FONT face=Arial size=2>the output is a bit noisy. You can hear a little
hissing noise, which seems to correspond to the envelope and therefore VCA
activity of the VCA between the output amplifier and distortion diodes
(controlled by "decay").</FONT></DIV>
<DIV> </DIV>
<DIV><FONT face=Arial size=2>What would you suggest to eliminate that (not very
loud) noise ? (Of course, this is not the noise of the noise generator, bleeding
through somehow, this is tested...)</FONT></DIV>
<DIV><FONT face=Arial size=2>Another opamp for the output-amplifier ? Something
better than the TL072 ? Something better than the BC549 for the VCA's
?</FONT></DIV>
<DIV> </DIV>
<DIV><FONT face=Arial size=2>cheers, Joerg</FONT></DIV></BODY></HTML>