<html><head><meta http-equiv="content-type" content="text/html; charset=utf-8"></head><body style="overflow-wrap: break-word; -webkit-nbsp-mode: space; line-break: after-white-space;"><div><div>On Dec 26, 2024, at 8:42 AM, The SynthiMuse via Synth-diy <synth-diy@synth-diy.org> wrote:</div><blockquote type="cite"><br class="Apple-interchange-newline"><div><div dir="auto"><div dir="auto"><div dir="auto">I guess there's a big overlap between synth-diy people and visitors to Hackaday but just in case anyone is interested; good article ( with some links to other articles embedded ) on Top Octave Generators.</div><div dir="auto"><br></div><div dir="auto"><a href="https://hackaday.com/2024/12/24/the-mystery-of-the-messed-up-hammond-x5/">https://hackaday.com/2024/12/24/the-mystery-of-the-messed-up-hammond-x5/</a></div></div></div></div></blockquote><br></div><div>Interesting.</div><div><br></div><div>There *must* be some spare MM5833's out there. At the very least from dead Hammond X5's or other organs that have been parts'd out. Or maybe a different TOG chip could be found and adapted.</div><div><br></div><div>But y'know... I can't help but think that it's downright weird to replace a TOG chip with a computer. Of course if it works, it works; certainly. It's just that the technological limitations of the day were so fundamental to the very nature of these instruments.</div><div><br></div><div>If it was me, I would have directly emulated the chip with, say, 6 CD4040's and some diodes. Which is probably exactly what the Hammond engineers did while they were building prototypes and waiting for the TOG chips to be delivered.</div><div><br></div><div>The top-octave-with-dividers approach to electronic organs has been around since the Baldwin Model 5, introduced in 1946. That's vacuum tubes, of course, and with the top octave being individually tuned oscillators. </div><div><br></div><div>Many years ago I pointed out on synth-diy that, plugging the numbers in, the TOG chips had roughly double the error of the Hammond tone wheels. And that I found that disappointing; all this technological development for significantly less accuracy. Of course that's because tonewheels have integers in both the numerator and denominator while TOG chips are stuck with just the denominator.</div><div><br></div><div> -- Don<br>--<br>Donald Tillman, Palo Alto, California<br>https://till.com</div><div><br></div><div><br></div><div><br></div><br></body></html>