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Real organs had to have every note (about a hundred) tuned using a hammer, so tuning twelve notes using pots should be easy 🙂</div>
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<div id="divRplyFwdMsg" dir="ltr"><font face="Calibri, sans-serif" style="font-size:11pt" color="#000000"><b>From:</b> Synth-diy <synth-diy-bounces@synth-diy.org> on behalf of Tom Wiltshire <tom@electricdruid.net><br>
<b>Sent:</b> 29 December 2024 21:15<br>
<b>To:</b> Michael E Caloroso <mec.forumreader@gmail.com><br>
<b>Cc:</b> synth-diy mailing list <synth-diy@synth-diy.org><br>
<b>Subject:</b> Re: [sdiy] Interesting article on top octave generators.</font>
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<div class="" style="word-wrap:break-word; line-break:after-white-space">The thing is it's got to the point where the *specific* divider ratios used by those TOG chips are now a key part of the "combo organ sound". Each generation's limitations becomes the
next generation's nostalgia...
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<div class="">Totally agree that twelve separate oscillators for the top octave is the better way though. It's not that hard, and the evidence from the numerous 1970's organs still in existence is that it improves the sound. Tuning twelve notes isn't so hard
that it should be avoided.</div>
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<div class="">Tom<br class="">
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<div class="">On 29 Dec 2024, at 20:11, Michael E Caloroso <<a href="mailto:mec.forumreader@gmail.com" class="">mec.forumreader@gmail.com</a>> wrote:</div>
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<div dir="ltr" class="">TOG or discrete dividers from a single master oscillator aren't going to produce a perfect equal tempered scale because the interval between equal tempered semitones isn't an integer ratio (the interval is an irrational number = 12th
root of 2).
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<div class="">If you want a true equal tempered scale, you have to use twelve tunable oscillators per semitone.</div>
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<div class="">MC</div>
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<div dir="ltr" class="x_gmail_attr">On Fri, Dec 27, 2024 at 4:09 PM Tom Wiltshire <<a href="mailto:tom@electricdruid.net" class="">tom@electricdruid.net</a>> wrote:<br class="">
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<div class="">On 27 Dec 2024, at 20:17, Ingo Debus via Synth-diy <<a href="mailto:synth-diy@synth-diy.org" target="_blank" class="">synth-diy@synth-diy.org</a>> wrote:</div>
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<div class="">Am 27.12.2024 um 08:35 schrieb Donald Tillman <<a href="mailto:don@till.com" target="_blank" class="">don@till.com</a>>:</div>
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<div class=""><span class="" style="font-family:Helvetica; font-size:14px; font-style:normal; font-variant-caps:normal; font-weight:normal; letter-spacing:normal; text-align:start; text-indent:0px; text-transform:none; white-space:normal; word-spacing:0px; text-decoration:none; float:none; display:inline">If
it was me, I would have directly emulated the chip with, say, 6 CD4040's and some diodes.</span></div>
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<div class="">That’s what Elektor did in 1974:</div>
<div class=""><a href="https://www.elektormagazine.de/magazine/elektor-197411/55706" target="_blank" class="">https://www.elektormagazine.de/magazine/elektor-197411/55706</a></div>
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<div class="">They used TTL chips, not CMOS. It was quite a huge project. I remember this so well because this was one of the first Elektor issues I bought myself.</div>
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<div class="">I honestly don't see the point of this type of approach. Discrete dividers has all of the worst features of the TOG chips (locked frequencies, poor frequency tuning, loads of circuit) without the few minor benefits (small size, simplicity, and
cheapness).
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<div class="">IF you'Re willing to throw that much circuitry at the problem, why would you *not* simply build a board with twelve top octave oscillators and then just use dividers from there? I don't get it.</div>
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<div class="">I suppose the draw of only having a *single' trimmer to tune the entire thing must have seemed absolutely magical in the late 1970's, and that was enough!!<br class="">
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<div class="">Tom</div>
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