Announcement

Collapse
No announcement yet.

Lowering the bottom manual by an octave

Collapse
This topic is closed.
X
X
  • Filter
  • Time
  • Show
Clear All
new posts

    Lowering the bottom manual by an octave

    I've been seeing videos on YouTube where the author claims to have lowered the bottom manual of his M-3 by an octave. Two questions: (1) how is that done? and (2) why would you do it?

    Thanks,

    Aaron
    Playing since December 30, 2011
    Wurlitzer 805 Centura Professional
    Hammond M101
    Crumar Roady
    Yamaha PSR-E423

    #2
    I forget the specifics (but lots of people here know and can explain in detail) but if I remember correctly it basically gives you a fuller bass sound out of a spinet. It helps to beef up left hand bass.

    I was planning on doing it on our M-111 but never got around to it.
    Keyboards: 1972 Fender Rhodes Stage 73, M-111, M-3, A-100, M2 Desk(!), B3!
    Spinny things: Wurlitzer Tone Cabs (500 and 420), PR-40, 31W, 31H, chopped 31H, 125 (empty cabinet), 30A!!!

    Comment


      #3
      Originally posted by Aaron2 View Post
      I've been seeing videos on YouTube where the author claims to have lowered the bottom manual of his M-3 by an octave. Two questions: (1) how is that done? and (2) why would you do it?

      Thanks,

      Aaron
      Second question first (why?):
      The lower manual on the M3 has no 16' or 5 2/3'. It starts with an 8' drawbar.
      So if you try to do things typical jazz/blues things like play a lick on the top manual, drop your right hand to the lower manual and play the same lick with a different tonal quality it doesn't work. And obviously playing any left hand bass is out of the question. The lack of the 5 2/3 also means you can't get what is called a difference or resultant tone. 8' + 5 2/3' creates a tone which is heard as being an octave lower than the 8'. This trick is used on pipe organs to create a 32' stop from a 16'.

      There are two solutions:
      You can either rewire all 396 contacts so that the top manual is wired an octave lower
      (took me about 10 days at a busbar per day but I also added foldback)
      or you can do it the easy way.

      Remove the black metal plate under the front of the organ covering where tone wheels 18-91 connect to the lower manual.
      Unsolder freqs #30-91 (or solder terminals 13 on up).
      Most of the wires aren't wrapped, you just heat and pull.
      Loop the first octave up to the second (add a wire from 1 to 13, 2-14... 12-24).
      Splice the wire originally at 13 to 25, 14-26...
      On the 12 wires that are left over use heat shrink wrap so they don't short out.
      You have now dropped the lower manual an octave and recovered a 5 2/3' stop (although it's the third drawbar not the second).
      See the blue freq numbers.
      This allows you to get freq 18 + freq 25 on the low F which will sound like the F on the foot pedals (Freq #6).

      Sometimes you can stretch all the wires up an octave and splice down an octave (13 to 1, 14-2...) but often that's not an option.
      Attached Files
      Last edited by sfp1954; 02-15-2012, 05:27 PM.
      1969 Hammond A-105, Leslie 22H, 1961 M3
      XK3-C, VK8-M, Boss RT-20, Neo Ventilator
      Roland XP-30 (3), XV-5080 (2), Various Fatar/Studiologic Weighted Contollers (SL-1100, 1176, 880)

      Comment


        #4
        Also see:
        http://www.organforum.com/forums/sho...ering-bass-mod
        1969 Hammond A-105, Leslie 22H, 1961 M3
        XK3-C, VK8-M, Boss RT-20, Neo Ventilator
        Roland XP-30 (3), XV-5080 (2), Various Fatar/Studiologic Weighted Contollers (SL-1100, 1176, 880)

        Comment


          #5
          Cor, you know your stuff, sfp!
          I didn't know that about the 32' substitution on pipes.

          I had a dig around in my photobucket account for these photos, they'll help illustrate the procedure.

          you unsolder the lot thusly, keeping the nasty poisonous smoke outta your nostrils if possible:



          reattach 'em 12 spaces along so the high notes now drop off the end like this:



          However, the harness won't reach that far, so you need to extend it.
          you can painstakingly add extensions or allow a bit more slack by shortening the obstacles:

          Here's where the harness comes out of my T500. I've bent the metal brace over here:



          (more to come. The current forum engine only allows three photos per post.)
          -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


            #6
            Then I drilled a hole thru the end brace on the lower manual:



            Here you can see the same procedure on an M3 by Geoff Williamson, the first guy I know who did the job:



            Much tidier than mine!


            and next to the bottom octave...
            -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


              #7
              Ahm, I was wrong about the three photos. Must be at least four.
              -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


                #8
                Yeah, so attaching 'em all back together you end up with an octave of blank terminals at the left hand (bass) end:



                So you can either add bass foldback by putting wire jumpers from the next octave up...



                or you can get bass all the way down (which actually goes lower than a B3) by either using an octave divider (there's a member here who makes 'em) or by filtering the pedal tonewheels into sine waves, if your spinet has those tonewheels.

                If you're curious about those I can dig the particulars out.
                -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

                Working...
                X