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<DIV><FONT face=Arial size=2>Hi Peng,</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>The SPDT center off switch should work.
That's On/Off/On, where the center position does not put the 7.5V on either
'throw'. If you note the original Buchla schematic, that is exactly
what Don Buchla used for a switch (the 'dot' in the middle of the
switch symbol is the center 'off' position). The 'Both' mode is actually
in effect when both the Low Pass and Gate mode switch logic signals are 0V (all
4016 switches are open). So, it's just how you have it now, just put that
SPDT center off switch in, and away you go.</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>Peter Grenader devised a method to avoid using the
4016's at all by installing a (IIRC) 3PDT center off switch, which makes things
a bit easier. However, I am using Mark's adaptation of the Low Pass Gate
using the 4016 mainly because 4016's are a helluva lot cheaper than those 3PDT
switches (but that's just me).</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>Cheers,</FONT></DIV>
<DIV><FONT face=Arial size=2>Scott</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV>----- Original Message ----- </DIV>
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style="PADDING-RIGHT: 0px; PADDING-LEFT: 5px; MARGIN-LEFT: 5px; BORDER-LEFT: #000000 2px solid; MARGIN-RIGHT: 0px">
<DIV
style="BACKGROUND: #e4e4e4; FONT: 10pt arial; font-color: black"><B>From:</B>
<A title=peng3002@yahoo.com href="mailto:peng3002@yahoo.com">Peng</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> Tuesday, August 10, 2004 8:57
PM</DIV>
<DIV style="FONT: 10pt arial"><B>Subject:</B> [sdiy] Buchla Lowpass Gate
Switch</DIV>
<DIV><BR></DIV>
<DIV>Hi,</DIV>
<DIV> </DIV>
<DIV> I recently finished the Lopass Gate using Mark Verbos pcb. Works
good. I put in a 2 position toggle to switch between lowpass/gate. I'd like to
have a "both" position but can't figure out how to do it ( experiencing a
brain freeze or something!). I have some SPDT center off and DPDT center off.
</DIV>
<DIV> I had an idea to replace the -7.5V that goes to 1M resistor on pcb
with +7.5V, then put </DIV>
<DIV>-7.5V to middle lug of toggle. That way, if it's in the center (off)
position, I'd get the both response ? Just a guess. </DIV>
<DIV> I searched this out in the archives first (of course) but didn't
find anything, though there are references made. As a side note: On the search
page of SDIY I typed in " Buchla Gate" - no results. Next tried "Buchla" -
many results. One read "Buchla 292 Lowpass Gate" - this should have come up on
first search. Next "Buchla Lowpass" - nothing. Lastly "Buchla 292" - got
results. Seems you need to get the words in order, or just try to get the
first word. Maybe I'm missing something ? If not, then it's a good thing to
keep in mind when searching ( or posting for that matter ).</DIV>
<DIV> </DIV>
<DIV>Thanks,</DIV>
<DIV>P.</DIV>
<P>
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