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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=MsoPlainText>Tony,<o:p></o:p></p><p class=MsoPlainText>Very good and informative details here you gave us all..<o:p></o:p></p><p class=MsoPlainText>I thought about this 'in phase' leading edges importance to get all the<o:p></o:p></p><p class=MsoPlainText>Generated footages alligned and mixable but <u>I was not sure<br>looking at the Hammond schematic and the flip-flop stages<o:p></o:p></u></p><p class=MsoPlainText>Here is why:<o:p></o:p></p><p class=MsoPlainText><o:p> </o:p></p><p class=MsoPlainText>If you look at each freq divider sections you will notice<o:p></o:p></p><p class=MsoPlainText>They are all made out of a pre-driver/inverter that produce<br>a going down pulse to trigger its associate FF and make it trip.<br>(They are : V3-pin 2, V3-pin 5, V6-pin 3, V8-pin 2 and V8-pin 5)<o:p></o:p></p><p class=MsoPlainText>Then you have their triggered FF itself using 2 stages of 6SN7.<o:p></o:p></p><p class=MsoPlainText><o:p> </o:p></p><p class=MsoPlainText>The problem I have is the following :<o:p></o:p></p><p class=MsoPlainText>For example if you look at the 2<sup>nd</sup> freq divider,<o:p></o:p></p><p class=MsoPlainText>To produce a going down pulse at V3-pin 5 you need<o:p></o:p></p><p class=MsoPlainText>A going up pulse generated by the preceding FF stage output.. here V4-pin2. Ok.<o:p></o:p></p><p class=MsoPlainText>But to make all the following freq dividers ‘in phase’ each FF’s<o:p></o:p></p><p class=MsoPlainText>should produce a going up pulse at their outputs to drive the next connected pre-driver/inverter..<o:p></o:p></p><p class=MsoPlainText>(FF’s outputs are : V5-pin2, V7-pin 5, V9-pin 2 and… <b>oupss !!! they chose V10-pin 2 instead of V10-pin 5 !!!) Why ???</b><o:p></o:p></p><p class=MsoPlainText>Despite the fact Hammond chose pin2 instead of pin5 of V10 on the last FF,<o:p></o:p></p><p class=MsoPlainText>And following my first interrogation on transistor FF’s on how they start at first<o:p></o:p></p><p class=MsoPlainText>How can I understand what makes all these freq dividers allign ?<o:p></o:p></p><p class=MsoPlainText>To make all of them alligned each divider section must :<o:p></o:p></p><p class=MsoPlainText>** input : receive a going up pulse<o:p></o:p></p><p class=MsoPlainText>** output : generate a going up pulse too !! (But how Hammond’s engineers could know what section of their FF will generate the right pulse phase ??)<o:p></o:p></p><p class=MsoPlainText><o:p> </o:p></p><p class=MsoPlainText>These were and still are my interrogations…<o:p></o:p></p><p class=MsoPlainText><o:p> </o:p></p><p class=MsoPlainText>BTW, My PIC project won’t have to deal with these Hammond ‘original FF’s behaviours’<o:p></o:p></p><p class=MsoPlainText>But will simply generate in phase pulses who will be passed thru the same HP filters Hammond used in this schematic..<o:p></o:p></p><p class=MsoPlainText><o:p> </o:p></p><p class=MsoPlainText><img width=1543 height=1029 style='width:16.0729in;height:10.7187in' id="Image_x0020_2" src="cid:image001.jpg@01DA54F3.13538E00"><o:p></o:p></p><p class=MsoPlainText><o:p> </o:p></p><p class=MsoPlainText>> <span lang=FR style='mso-fareast-language:FR-CA'>-----Message d'origine-----</span></p><p class=MsoPlainText>> <span lang=FR style='mso-fareast-language:FR-CA'>De : Synth-diy <synth-diy-bounces@synth-diy.org> De la part de Tony Allgood</span></p><p class=MsoPlainText>> <span lang=FR style='mso-fareast-language:FR-CA'>via Synth-diy</span></p><p class=MsoPlainText>> <span lang=FR style='mso-fareast-language:FR-CA'>Envoyé : 1 février 2024 05:36</span></p><p class=MsoPlainText>> <span lang=FR style='mso-fareast-language:FR-CA'>À : Synth DIY <synth-diy@synth-diy.org></span></p><p class=MsoPlainText>> <span lang=FR style='mso-fareast-language:FR-CA'>Objet : Re: [sdiy] Now tube type (6SN7) flip-flop circuit.. Follow up...</span></p><p class=MsoPlainText>> </p><p class=MsoPlainText>> If you are creating pulse waves, or a pulse like wave, from the output of the</p><p class=MsoPlainText>> flip flop, it is important to consider the phase relationship of the flip-flop</p><p class=MsoPlainText>> outputs all together. Phase matters not if you listen to these derived pulse</p><p class=MsoPlainText>> outputs individually, but on an organ, or string machine, octaves are mixed</p><p class=MsoPlainText>> together, either by playing octaves on the keyboard or using the footage</p><p class=MsoPlainText>> mixers. If you don't have the correct phase relationship the resultant mix will</p><p class=MsoPlainText>> sound weak.</p><p class=MsoPlainText>> </p><p class=MsoPlainText>> Using a cascade of flip-flops to divide down will result in a set of square waves.</p><p class=MsoPlainText>> If the pulse is being created by a standard differentiator, a high pass CR circuit,</p><p class=MsoPlainText>> then it is the position in time of the leading edge of the output square wave</p><p class=MsoPlainText>> that is important. Those leading edges must line up, so that the leading edge</p><p class=MsoPlainText>> of the lowest frequency must be synchronised with all the others. That is,</p><p class=MsoPlainText>> when the lowest octave square wave goes up, then so must all the others.</p><p class=MsoPlainText>> </p><p class=MsoPlainText>> Note that the propagation delay within the chip itself is minimal and can be</p><p class=MsoPlainText>> ignored.</p><p class=MsoPlainText>> </p><p class=MsoPlainText>> How do I know this? I designed a SAJ110 octave divider replacement board for</p><p class=MsoPlainText>> string machines. The scope outputs looked perfect. But it sounded like pants</p><p class=MsoPlainText>> because every other octave when played together destructively interfered and</p><p class=MsoPlainText>> sounded wrong. It used the 4520 to divide the octaves.</p><p class=MsoPlainText>> </p><p class=MsoPlainText>> The problem was solved when I ensured the leading edges of all the were</p><p class=MsoPlainText>> synchronised. I could have done this with additional invertors, but it was</p><p class=MsoPlainText>> smaller to do it with a couple more 4520 stages. Now when you mixed octaves</p><p class=MsoPlainText>> the sound become louder.</p><p class=MsoPlainText>> </p><p class=MsoPlainText>> At this point I should present a diagram to show this. But I've lost my original</p><p class=MsoPlainText>> sketches I did on graph paper to show how the waveforms add together. If I</p><p class=MsoPlainText>> find it I'll post it.</p><p class=MsoPlainText>> </p><p class=MsoPlainText>> Tony</p><p class=MsoPlainText>> </p><p class=MsoPlainText>> <a href="http://www.oakleysound.com"><span style='color:windowtext;text-decoration:none'>www.oakleysound.com</span></a></p><p class=MsoPlainText>> </p><p class=MsoPlainText>> ________________________________________________________</p><p class=MsoPlainText>> This is the Synth-diy mailing list</p><p class=MsoPlainText>> Submit email to: <a href="mailto:Synth-diy@synth-diy.org"><span style='color:windowtext;text-decoration:none'>Synth-diy@synth-diy.org</span></a> View archive at: <a href="https://synth-diy.org/pipermail/synth-diy/"><span style='color:windowtext;text-decoration:none'>https://synth-</span></a></p><p class=MsoPlainText><a href="https://synth-diy.org/pipermail/synth-diy/"><span style='color:windowtext;text-decoration:none'>> diy.org/pipermail/synth-diy/</span></a></p><p class=MsoPlainText>> Check your settings at: <a href="https://synth-diy.org/mailman/listinfo/synth-diy"><span style='color:windowtext;text-decoration:none'>https://synth-diy.org/mailman/listinfo/synth-diy</span></a></p><p class=MsoPlainText>> Selling or trading? 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