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<DIV>Hi Chris,</DIV>
<DIV> </DIV>
<DIV>I am of the opinion that with the footage control set to the 1' rage and
with all other control inputs at 0V that the VCO should follow the conventional
MIDI-Note range as listed here <<A
href="http://www.elby-designs.com.midi-cv/midi-note-table.pdf">http://www.elby-designs.com.midi-cv/midi-note-table.pdf</A>></DIV>
<DIV><BR>Best Regards</DIV>
<DIV> </DIV>
<DIV>(Mr) Laurie Biddulph<BR>Mobile: 0404 846 943</DIV>
<DIV> </DIV>
<DIV>Elby Designs<BR>ABN: 70 022 727 605<BR><A
href="http://www.elby-designs.com">http://www.elby-designs.com</A></DIV>
<DIV> </DIV>
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<DIV style="FONT: 10pt arial">----- Original Message ----- </DIV>
<DIV
style="BACKGROUND: #e4e4e4; FONT: 10pt arial; font-color: black"><B>From:</B>
<A title=wight446@yahoo.com href="mailto:wight446@yahoo.com">Chris Manders</A>
</DIV>
<DIV style="FONT: 10pt arial"><B>To:</B> <A title=synth-diy@dropmix.xs4all.nl
href="mailto:synth-diy@dropmix.xs4all.nl">synth-diy@dropmix.xs4all.nl</A>
</DIV>
<DIV style="FONT: 10pt arial"><B>Sent:</B> Monday, March 06, 2006 9:45
AM</DIV>
<DIV style="FONT: 10pt arial"><B>Subject:</B> [sdiy] Two questions - VCO
standards and Differential Op-Amp Circuit</DIV>
<DIV><BR></DIV>Hi folks<BR><BR>Just two questions I have for you knowledgeable
guys<BR>to answer, please?<BR><BR>Regarding VCOs. Is there some sort of
standard<BR>Frequency output setting? i.e. with the CV input at<BR>Zero (or
disconnected) the VCO tunes exactly to Middle<BR>C? This would seem
appropriate perhaps? Or is it best<BR>to set them to a very low level, as the
CV inputs will<BR>generally be positive and cause a rising of pitch?<BR>My
VCOs work fine (built on breadboard) but I have not<BR>set them up yet for
anything specific. I know that I<BR>could set them up for anything I wanted
but I would<BR>like to adopt an appropriate standard if there is
one.<BR><BR>Secondly, and on a different subject – Say I have an<BR>Op-Amp
stage set as a differential amplifier, and<BR>running from a single 15 volt
supply. If I set the<BR>inputs up so that the output should be a
negative<BR>voltage, would it damage the Op-Amp as it couldn’t<BR>output this
negative voltage as it is powered from a<BR>single supply rail?<BR>For this
situation, would the output of the Op-Amp be<BR>an inverted positive
difference, or would the Op-Amp<BR>output be Zero for all negative results
like this?<BR><BR>Thank you in
advance<BR>Chris<BR><BR><BR>__________________________________________________<BR>Do
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