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Best way to do tapering on an M3

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  • Best way to do tapering on an M3

    I recently upgraded one of my M3's with the full upper foldback mod with parts from an M100 I parted out a while ago. It sounds incredible, but I want to take it to the next level and add tapering, and I was wondering how the best way to go about this is. The main way I've seen this done is that you replace the resistance wire with normal wire and run a resistor in series of the new tapered value. This value is usually 10 ohms, I presume because that's what the B3 tapering had for the top octave of the highest 3 drawbars. However, the value for most contacts on the organ is 24 ohms, as opposed to the 16 ohm standard you see in an M3. This creates a net decibel increase of 7 dB. I can't imagine that using a 10 ohm resistor in something with a 16 ohm standard would also increase the sound by 7 decibels. Would you instead want to use 2 ohm resistors so you have the same net 14 ohms and +7 dB? I haven't seen anyone do this but it seems more logical to me.

    Also, I was thinking about instead of replacing the wires which sounds like a mess, just cutting the wire, and trimming it down to the right resistance value. Since those wires are pretty long I think that cutting it down to 10 ohm would still give it enough length. This would probably not be the case for 2 ohms though.

    Any help or thoughts on this idea are greatly appreciated.
    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
    well.. i hope these thoughts are helpful....

    It's called "tapering" because there isn't a "standard value" -- not in the consoles. HammondWiki is a good reference in this matter.
    It is a standard value in spinets.

    What you suggest is completely doable. Hey, it's only time and trouble.

    If you've already added busbars and contacts, then resistance change is pretty much a hardware exercise exactly as you say. I've soldered bunches of resistors onto the backs of contacts (prior to installation - they're a total pain to do while in the manual). But while resistance helps to predict amplitude and relative output, ultimately it comes down to the actual p-p volts at each tone and terminal.

    Because I've only added resistors to added spinet contacts, I've never considered reloading the whole wire loom, which sounds like what you're after. That seems like a colossal amount of touch-time for a rather middling payoff that can be pretty closely emulated by some TG re-voicing. That, i've done. Took some bumps out. Put some ice in. Again, HammondWiki has those output maps and are good references for basing relative outputs. Obviously, it still comes down to your ears. I've never gotten it right the first time.

    Just like any other intrusive mod, opinions of such an undertaking will always differ. Some will say, "no problem, have at it," and others will say "You're gonna ruin your organ!" Both have valid points. My experience has been that big changes of this sort sometimes work out exactly as planned and lucky you. At the same time, nothing is ever "ruined". It just turns into a bigger project (which it always does, anyway).

    You could really have a screamer when you're done.






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    • #3
      What I'm mainly referring to is that many of the contacts in a console are 24 ohm, which is the 0 dB pass through point. The tapered top octaves have resistance values of 10 ohms, giving them + 7dB. Given that M3's are not 0 dB at 24 ohms and have a standard 16 ohm, which I guess you could call 0 dB. This being said, putting 10 ohm resistors in would not create + 7 dB, like how many taper mods do it. Would this mean that you'd want to put some other resistance value in here? That's my main concern/question.
      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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      • #4
        Hi Alek, the main problem with cutting the resistance wires to the correct length is the impracticality of unspooling... The normal mod usually leaves the existing wire in the spool and puts a resistor and plain wire in parallel with the existing wire, so no removal required.
        -1958 Hofner 550 archtop guitar -1959 C3 and PR40- -1964 Busillachio Harmonium- -1964 M101-
        -1967ish Leslie 122- -1975 T500 (modded..chopped, and reassembled!)-
        -DIY 760 FrankenLeslie/rat hideout-
        -1980 Electrokey Electric Piano- -Yamaha electric Harmonium (early 80's?)-
        -1990 Jansen GMF150 amp- -1992 Korg 01W/fd- -1992 G&L S-500 geetar.

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        • #5
          By the way, here's Carsten Meyer's chart on the tapering for all Hammond models... SO GOOD!
          https://www.keyboardpartner.de/hammo...rdTapering.png
          -1958 Hofner 550 archtop guitar -1959 C3 and PR40- -1964 Busillachio Harmonium- -1964 M101-
          -1967ish Leslie 122- -1975 T500 (modded..chopped, and reassembled!)-
          -DIY 760 FrankenLeslie/rat hideout-
          -1980 Electrokey Electric Piano- -Yamaha electric Harmonium (early 80's?)-
          -1990 Jansen GMF150 amp- -1992 Korg 01W/fd- -1992 G&L S-500 geetar.

          Comment

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