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</o:shapelayout></xml><![endif]--></head><body lang=FR-CA link=blue vlink=purple style='word-wrap:break-word'><div class=WordSection1><p class=MsoNormal><span style='mso-fareast-language:EN-US'>For those who would like to hear what an Hammond RT2 pedal Solo board sounds like :<o:p></o:p></span></p><p class=MsoNormal><span style='mso-fareast-language:EN-US'><o:p> </o:p></span></p><p class=MsoNormal><span style='mso-fareast-language:EN-US'><a href="https://www.youtube.com/watch?v=q7M6_kO5S4k&t=421s">https://www.youtube.com/watch?v=q7M6_kO5S4k&t=421s</a><o:p></o:p></span></p><p class=MsoNormal><span style='mso-fareast-language:EN-US'><o:p> </o:p></span></p><p class=MsoNormal><span style='mso-fareast-language:EN-US'>Since this is a short demo, the sound is very flat and straight.<o:p></o:p></span></p><p class=MsoNormal><span style='mso-fareast-language:EN-US'>My project will use a digital reverb module to add some ‘church’ ambience !<o:p></o:p></span></p><p class=MsoNormal><span style='mso-fareast-language:EN-US'><o:p> </o:p></span></p><p class=MsoNormal><span style='mso-fareast-language:EN-US'>Thanks for all your comments.<o:p></o:p></span></p><p class=MsoNormal><span style='mso-fareast-language:EN-US'>As usual this will clarify things and help me a lot !<o:p></o:p></span></p><p class=MsoNormal><span style='mso-fareast-language:EN-US'>And.. yes this will be a MIDI controlled Pedal Solo generator.<o:p></o:p></span></p><p class=MsoNormal><span style='mso-fareast-language:EN-US'><o:p> </o:p></span></p><p class=MsoNormal><span style='mso-fareast-language:EN-US'>Cheers !<o:p></o:p></span></p><p class=MsoNormal><span style='mso-fareast-language:EN-US'><o:p> </o:p></span></p><div style='border:none;border-left:solid blue 1.5pt;padding:0cm 0cm 0cm 4.0pt'><div><div style='border:none;border-top:solid #E1E1E1 1.0pt;padding:3.0pt 0cm 0cm 0cm'><p class=MsoNormal><b><span lang=FR>De :</span></b><span lang=FR> Synth-diy <synth-diy-bounces@synth-diy.org> <b>De la part de</b> Jean-Pierre Desrochers<br><b>Envoyé :</b> 31 janvier 2024 16:31<br><b>À :</b> synth-diy@synth-diy.org<br><b>Objet :</b> [sdiy] Now tube type (6SN7) flip-flop circuit.. Follow up...<o:p></o:p></span></p></div></div><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal><span style='mso-fareast-language:EN-US'>I asked this question about flip-flops because I have a new project in mind..<o:p></o:p></span></p><p class=MsoNormal><span style='mso-fareast-language:EN-US'>I once had a vintage Hammond RT2 organ with a wide church type pedal board.<o:p></o:p></span></p><p class=MsoNormal><span style='mso-fareast-language:EN-US'>This pedal board sounded amazingly beautifull !<o:p></o:p></span></p><p class=MsoNormal><span style='mso-fareast-language:EN-US'>This pedal board sound was produced by a bunch of successive flip-flops made out of 6SN7 triode tubes<o:p></o:p></span></p><p class=MsoNormal><span style='mso-fareast-language:EN-US'>In a chain distribution.. Producing all the needed pipes sounds (1’, 2’, 4’, 8’, 16’, 32’).<br>I thought I could reproduce these sounds using a simple CD4040 counter,<o:p></o:p></span></p><p class=MsoNormal><span style='mso-fareast-language:EN-US'>Or best, a PIC micro that would have MIDI input and take care of all the push buttons/leds<o:p></o:p></span></p><p class=MsoNormal><span style='mso-fareast-language:EN-US'>That select the actual footages, AND generate all the successive square waves (yes, these flip-flops have roughly shaped square waves output)<br>to be filtered using Hammond’s filters design.<br>Have a look at the below ‘Hammond RT2 PedaL Solo’ schematic ..<o:p></o:p></span></p><p class=MsoNormal><span style='mso-fareast-language:EN-US'>As you will see the actual waveforms kept to be filtered are derivated going down short pulses<o:p></o:p></span></p><p class=MsoNormal><span style='mso-fareast-language:EN-US'>From each flip-flops output like this :<o:p></o:p></span></p><p class=MsoNormal><span style='mso-fareast-language:EN-US'><img border=0 width=1136 height=247 style='width:11.8333in;height:2.5729in' id="Image_x0020_3" src="cid:image002.png@01DA5478.7EBAA1E0"></span><span style='mso-fareast-language:EN-US'><o:p></o:p></span></p><p class=MsoNormal><span style='mso-fareast-language:EN-US'><o:p> </o:p></span></p><p class=MsoNormal><span style='mso-fareast-language:EN-US'>These pulse are filtered by successive low pass filters and mixed together to the final output.<o:p></o:p></span></p><p class=MsoNormal><span style='mso-fareast-language:EN-US'>But to be a good Hammond pedal simulation I need to know the actual phase of each flip-flop outputs<o:p></o:p></span></p><p class=MsoNormal><span style='mso-fareast-language:EN-US'>Against each others..<o:p></o:p></span></p><p class=MsoNormal><span style='mso-fareast-language:EN-US'>Are these FF’s changing states on each preceding FF on going down or going up situation ?<o:p></o:p></span></p><p class=MsoNormal><span style='mso-fareast-language:EN-US'>I did not measure these waveforms in the past BUT I do know<br>each FF change state on the ‘going down’ pulse of its pre-driver.<o:p></o:p></span></p><p class=MsoNormal><span style='mso-fareast-language:EN-US'>I think using all the 6SN7 tubes output (always inverting their inputs)<o:p></o:p></span></p><p class=MsoNormal><span style='mso-fareast-language:EN-US'>I could figure out all the waveforms in this schematic but I’m not sure at all..<o:p></o:p></span></p><p class=MsoNormal><span style='mso-fareast-language:EN-US'><o:p> </o:p></span></p><p class=MsoNormal><span style='mso-fareast-language:EN-US'>BTW, I made a LTSpice simulation using this schematic with all the same components<br>including all the necessary 6SN7 (and the two 6J5’s V1 & V6)<o:p></o:p></span></p><p class=MsoNormal><span style='mso-fareast-language:EN-US'>And had very bad results.. noisy unreadable waveforms on many places..<o:p></o:p></span></p><p class=MsoNormal><span style='mso-fareast-language:EN-US'><o:p> </o:p></span></p><p class=MsoNormal><span style='mso-fareast-language:EN-US'>What do you think about the actual phasings of all the FF’s square wave output against each others ?<o:p></o:p></span></p><p class=MsoNormal><span style='mso-fareast-language:EN-US'><o:p> </o:p></span></p><p class=MsoNormal><span style='mso-fareast-language:EN-US'>JP<o:p></o:p></span></p><p class=MsoNormal><span style='mso-fareast-language:EN-US'><o:p> </o:p></span></p><p class=MsoNormal><span style='mso-fareast-language:EN-US'><img border=0 width=1543 height=1029 style='width:16.0729in;height:10.7187in' id="Image_x0020_2" src="cid:image003.jpg@01DA5478.7EBAA1E0"></span><span style='mso-fareast-language:EN-US'><o:p></o:p></span></p><p class=MsoNormal><span style='mso-fareast-language:EN-US'><o:p> </o:p></span></p><div style='border:none;border-left:solid blue 1.5pt;padding:0cm 0cm 0cm 4.0pt'><div><div style='border:none;border-top:solid #E1E1E1 1.0pt;padding:3.0pt 0cm 0cm 0cm'><p class=MsoNormal><b><span lang=FR>De :</span></b><span lang=FR> Synth-diy <<a href="mailto:synth-diy-bounces@synth-diy.org">synth-diy-bounces@synth-diy.org</a>> <b>De la part de</b> Jean-Pierre Desrochers<br><b>Envoyé :</b> 31 janvier 2024 10:43<br><b>À :</b> <a href="mailto:synth-diy@synth-diy.org">synth-diy@synth-diy.org</a><br><b>Objet :</b> [sdiy] Transistor type flip-flop circuit.. What makes the 'power up' state of it ?<o:p></o:p></span></p></div></div><p class=MsoNormal><o:p> </o:p></p><p class=MsoPlainText>Hi list,<o:p></o:p></p><p class=MsoPlainText><span style='color:black'>I have a question about the behaviour of transistor type flip-flop circuit<o:p></o:p></span></p><p class=MsoPlainText><span style='color:black'>When the DC power is applied to it..<o:p></o:p></span></p><p class=MsoPlainText><span style='color:black'>The following schematic of Boss CE-2 pedal shows the flip-flop at the bottom right.<o:p></o:p></span></p><p class=MsoPlainText><span style='color:black'>Why when the DC power is applied : collector of Q6 goes high (to make the pedal in the ‘no effect’)<o:p></o:p></span></p><p class=MsoPlainText><span style='color:black'>And it’s not Q7 that goes this way instead ?<o:p></o:p></span></p><p class=MsoPlainText><span style='color:black'>I know that C23 (.01uf) pull down the trigger input when DC is applied<br>to put the pedal in the ‘no effect’ position, but why is Q6 selected ?<o:p></o:p></span></p><p class=MsoPlainText><span style='color:black'>This is a ‘balanced’ flip flop circuit and both sides should behaves the same<o:p></o:p></span></p><p class=MsoPlainText><span style='color:black'>But some kind of selection is done here.<o:p></o:p></span></p><p class=MsoPlainText><span style='color:black'><o:p> </o:p></span></p><p class=MsoPlainText><span style='color:black'>Could someone explain that behaviour ?<o:p></o:p></span></p><p class=MsoPlainText><o:p> </o:p></p><p class=MsoPlainText><span style='mso-ligatures:none'><img border=0 width=896 height=536 style='width:9.3333in;height:5.5833in' id="Image_x0020_1" src="cid:image004.jpg@01DA5478.7EBAA1E0"></span><span style='color:black'><o:p></o:p></span></p></div></div></div></body></html>