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<DIV><FONT face=Arial size=2>preciate that jay.. good
article.. it'll prob take me a bit to get through the math tho.. lol
.. :-) time to break out my math book from last
semester.. </FONT></DIV>
<DIV> </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="FONT: 10pt arial">----- Original Message ----- </DIV>
<DIV
style="BACKGROUND: #e4e4e4; FONT: 10pt arial; font-color: black"><B>From:</B>
<A title=jays@aracnet.com href="mailto:jays@aracnet.com">Jay
Schwichtenberg</A> </DIV>
<DIV style="FONT: 10pt arial"><B>To:</B> <A title=wberzinskas@nc.rr.com
href="mailto:wberzinskas@nc.rr.com">Bill Berzinskas</A> ; <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> Thursday, March 17, 2005 11:10
AM</DIV>
<DIV style="FONT: 10pt arial"><B>Subject:</B> RE: [sdiy] 5v ADV Bass / AD EG
Question.</DIV>
<DIV><BR></DIV>
<DIV><FONT face=Arial color=#0000ff size=2><SPAN
class=902140216-17032005>Bill,</SPAN></FONT></DIV>
<DIV><FONT face=Arial color=#0000ff size=2><SPAN
class=902140216-17032005></SPAN></FONT> </DIV>
<DIV><FONT face=Arial color=#0000ff size=2><SPAN
class=902140216-17032005>2)</SPAN></FONT></DIV>
<DIV><FONT face=Arial color=#0000ff size=2><SPAN
class=902140216-17032005></SPAN></FONT> </DIV>
<DIV><FONT size=+0><SPAN class=902140216-17032005><FONT face=Arial
color=#0000ff size=2>Another issue is that the attack, decay and release pots
on envelope generators are typically log pots, a non-linear scale. So if
the digital pots you use are not log they may not give you the timing
resolution that you are use to. One techinque to do that is buffer the pot and
add a resistor. Picking the right resistor and placing it between the wiper
and the other ends of the pot (assuming using pot as attenuator between signal
and gnd) can give you log or expo curves. Try </FONT><A
href="http://www.geofex.com/Article_Folders/potsecrets/potscret.htm"><FONT
face=Arial color=#0000ff
size=2>http://www.geofex.com/Article_Folders/potsecrets/potscret.htm</FONT></A><FONT
face=Arial color=#0000ff size=2> </FONT></SPAN></FONT><SPAN
class=902140216-17032005><FONT face=Arial color=#0000ff size=2>for that
info.</FONT></SPAN></DIV>
<DIV><SPAN class=902140216-17032005><FONT face=Arial color=#0000ff
size=2></FONT></SPAN> </DIV>
<DIV><SPAN class=902140216-17032005><FONT face=Arial color=#0000ff size=2>Good
luck.</FONT></SPAN></DIV>
<DIV><SPAN class=902140216-17032005><FONT face=Arial color=#0000ff size=2>Jay
S.</FONT></SPAN></DIV>
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<DIV class=OutlookMessageHeader dir=ltr align=left><FONT face=Tahoma
size=2>-----Original Message-----<BR><B>From:</B>
owner-synth-diy@dropmix.xs4all.nl
[mailto:owner-synth-diy@dropmix.xs4all.nl]<B>On Behalf Of </B>Bill
Berzinskas<BR><B>Sent:</B> Thursday, March 17, 2005 7:36 AM<BR><B>To:</B>
synth-diy@dropmix.xs4all.nl<BR><B>Subject:</B> [sdiy] 5v ADV Bass / AD EG
Question. <BR><BR></FONT></DIV>
<DIV><FONT face=Arial size=2>Hello everybody.. just woke up to a crazy
little burst of snow here in NC.. wierd.. </FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>Anyhow.. As you probably know i'm
modding the bejezzus out of my adv-bass.. In my quest to make it
digitally controlled, i've hit a few snags.. so maybe you can help me
out.. </FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>1) I am converting it to digital
control.. mostly thru digital pots.. a few things with
DAC.. so.. for the digital pots, i have to use 5v input, and rather
then use way more opamps then i want to deal with, i would like to make it
operate on 5v possibly with a bipolar or just 12v output stage if
necessary.. So.. </FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>I've done some crude experiments with the
Trigger section just to see how it reacts to switching from +/-12v to just
+5v.. I've tried with tl082s.. and i just can't get
the trigger ratio right.. and it always triggers.. so.. since i broke down
and got a few lm324s, i tried those.. and it seems to be working
correctly.. i then went on and built the impact part using the
digital potentiometers.. all good so far.. if i just
switch all my opamps in the design, will it carry through the rest of the
circuit properly? </FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>2) I plan to use a digital potentiometer
to control the decay time.. but the highest value i can come up
with is 100k.. so i'm thinking i can change the capacitor and get about the
same decay time? any recommendations for a value? </FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>thanks guys! :-) </FONT></DIV>
<DIV><FONT face=Arial size=2>--billie</FONT></DIV>
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