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M3 Bass pedal tones

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  • M3 Bass pedal tones

    So obviously the bass pedals on an M3 and other M series organs sound like different than the notes on the manuals, almost like a tuba, which I don't like a whole lot. What I was wondering was if this was due to some oddly shaped tonewheel in the generator, or if it is due to going through the pedal amplifier. I'm going to assume the former because tonewheels 6 and 18 for example (6 on the pedals and 18 on the manuals) sound different but produce the same frequency. Is it correct that it sounds different due to the tonewheel? I'm just doing some wishful thinking in that the bass pedal tonewheels could sound like the manual tones if they somehow went through the intermediate manual, or if I wired them into the manuals with my foldback plan that I made, before finding out I was missing tones... If anyone knows more on this topic please let me know, thanks!
    1949 Hammond CV w/1960 Leslie 45 (converted to 145), using H-1 and Leslie 25 amp
    1958 & 63 Hammond M3
    1963 Hammond L100 with 70s Leslie 120
    1979 Rhodes Piano

  • #2
    If I'm not mistaken, the pedal tonewheels are a bit different from the others, and there is also a kind of filter for each tonewheel to make them sound richer in harmonics than a single tonewheel. Experts might correct me on that.
    Have you heard the pedals on an M100? I have both an M100 and an M3, and in my opinion, the M100's pedals sound better and deeper, and are closer to a console's pedals. I find that the pedals in my M100, along with lower manual octave drop mod, are suitable for playing "bass" in an organ trio setting, even though it's not quite a console.
    What I do know is that there are two additional capacitors in the pedal amplifier of the M100's preamp. Whether or not this is the only difference, I don't know, but if it is, then it would be a pretty simple modification to improve the M3's pedals. I might very well try it on my M3.
    A100, X77, M3, M100, E100
    Leslie 147, 145, homemade road Leslie
    My youtube channel

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    • #3
      The first 13 wheels are not shaped like everyone else. The regular wheel is a nice, smooth, undulating wave. Lobes, if you will. As freqs get higher, they look almost like fine toothed gears. Still trying to produce a sine wave, and it really does.

      The pedal wheels have notches. Yup. Squared off notches and, predictably, have a greater square wave component. Theoretically, sine waves have no overtones. Hammonds are close enough for this to be basically true. This allows the drawbars to work without a lotta muddiness. Square waves contain odd-numbered overtones. Mr. Fourier showed us that centuries ago.

      The spinet models were made for quiet surroundings. There's only the one pedal drawbar -which is nothing more than continuous volume - for the peds. Can't have things getting outta hand, right? But at low freqs, a straight sine would get lost in the sauce pretty easily at those volumes with nothing on top for definition. So the pedals were 'thickened' with a different wave -- how that 'character' was all decided is, of course, long gone.

      While the remaining resonance circuitry might do something, I tend to think it's not much. Sure, sending harmonics down that LC circuit is gonna do something diff, but when you see the actual tonewheel, you'll know there's very obviously something different going on. Big chunks are notched out.

      Short of replacing the TG with a console unit (yeah, right) or better yet, doing some surgery and replacing individual tonewheels (did I mention i'm selling a bridge?), your options are limited. Conceivably a guy could build a filter circuit around a quad op amp and smooth things out to be more sinusoidal. That'd be 13X circuits. Not unthinkable and arguably less work than the other options.

      OR, you could do like I did on one of mine. I just fabbed a separate bass unit, not dependent upon the TG, and ran things that way. Kind of a kluge, but you get the bass you want it. Just an idea or two.

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      • #4
        Thank you this is helpful in me not giving up hope haha. I previously owned an M100 which I parted out because it was just barely functional and I had 2 M3's, one of which needed some parts. I do not recall how the pedal tones sounded though, I just remember that they were bad, much like my M3, but as you said maybe a little better. My goal in finding this stuff out is that I could clean the tones up, and use a scheme I already made for a lower manual octave drop where the lower manual is basically wired with foldback as a console manual, from the lowest F. In this, the lowest drawbar would go up from F (tonewheel 18) and then drop down to a lower C (pedal C, tonewheel #1 on M3 TG) and go up from there. I have all the plans, I just know that without cleaning up those pedal tones it won't sound like how I want it to. However if the tonewheel is a different shape this will obviously not sound good as it won't match the rest of the tonewheels in tonality, regardless of how the pedals get their tones. I suppose I should just pop up the TG and look into it from the bottom to observe the tonewheel shapes, thanks again for your reply though.
        1949 Hammond CV w/1960 Leslie 45 (converted to 145), using H-1 and Leslie 25 amp
        1958 & 63 Hammond M3
        1963 Hammond L100 with 70s Leslie 120
        1979 Rhodes Piano

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        • #5
          And thank you tiredoldgeezer for your response as well. Putting in a console TG would be great, but like you said, a joke... Doing surgery and replacing individual tonewheels could also work, but then of course I'd need to get new tonewheels, and take apart that castle of a TG and somehow get it back together in one piece, which sounds not only nearly impossible (for me at least), but would also just be beyond the point of waaaayyyy too much work for not enough gain. Anyway, I can just brain up another bass foldback scheme, thank you guys for you input.
          1949 Hammond CV w/1960 Leslie 45 (converted to 145), using H-1 and Leslie 25 amp
          1958 & 63 Hammond M3
          1963 Hammond L100 with 70s Leslie 120
          1979 Rhodes Piano

          Comment

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