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</o:shapelayout></xml><![endif]--></head><body lang=EN-US link=blue vlink=purple><div class=WordSection1><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><o:p> </o:p></span></p><div><div><p class=MsoNormal><o:p> </o:p></p><div><div><p class=MsoNormal>On Mon, 20 Mar 2017 16:58 Elain Klopke, <<a href="mailto:functionofform@gmail.com">functionofform@gmail.com</a>> wrote:<o:p></o:p></p></div><blockquote style='border:none;border-left:solid #CCCCCC 1.0pt;padding:0in 0in 0in 6.0pt;margin-left:4.8pt;margin-right:0in'><div><p class=MsoNormal>So I'm going to put this can of worms on the table and back off slowly before opening it....<o:p></o:p></p><div><p class=MsoNormal><o:p> </o:p></p></div><div><p class=MsoNormal>Due to various reasons (not the least of which was getting shafted by the person I purchased a large quantity of LDRs from) I'm switching over to an AR envelope generator and VCA combo for keying my notes on the paraphonic synth. <br><br>I decided to go with some circuits that I know and have assembled a few times, the AR generator and VCA from Ray Wilson's original Sound Lab mini synth. I'm going to try to trim away the bits of the AR generator that have to do with the triggered mode since these are going to be gated by the key presses only and see if they still work.<br><br>Question time: Ray's VCA is a simple half-a-LM13700 with the CV going into the Bias input and the op amp bit doing its amplify-y thing.<o:p></o:p></p></div><div><p class=MsoNormal><o:p> </o:p></p></div><div><p class=MsoNormal>1) In his notes, Ray talks about the response to the CV being linear. Since I'm just using this to switch the notes to the rest of the synth with a little preset attack and release that shouldn't be a problem, right? It would only do strange things if I tried feeding it an exponential envelope from an external source?<o:p></o:p></p></div><div><p class=MsoNormal><o:p> </o:p></p></div><div><p class=MsoNormal>2) If I hard-wire the initial gain "knob" to no initial gain, it's going to be silent until the envelope hits it?<o:p></o:p></p></div><div><p class=MsoNormal><o:p> </o:p></p></div><div><p class=MsoNormal>3) Is there any noticeable difference between an LM13700, NJM13700, and NJM13600 besides the price? Because at 148 chips for a 3-octave keyboard, price is kinda a thing.<o:p></o:p></p></div><div><p class=MsoNormal><o:p> </o:p></p></div><div><p class=MsoNormal>-Ian<o:p></o:p></p></div></div><p class=MsoNormal style='margin-left:11.55pt'>_______________________________________________<o:p></o:p></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><o:p> </o:p></span></p></blockquote></div></div><p class=MsoNormal><span style='color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>Hi Ian<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>I have used the NJM13600 and NJM13700 almost exclusively and have had no problems in any of the circuits I’ve tried. I have little experience with “real” LM13xxx however….<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>Dave M<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><o:p> </o:p></span></p></div></div></body></html>