Results 1 to 8 of 8

Thread: Lowering the bottom manual by an octave

  1. #1
    pp Pianissimo Aaron2's Avatar
    Join Date
    Dec 2011
    Location
    Phoenix, Arizona
    Posts
    131

    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. #2
    ff Fortissimo torea's Avatar
    Join Date
    Apr 2011
    Location
    There, CA
    Posts
    2,080

    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!!!

  3. #3
    ff Fortissimo sfp1954's Avatar
    Join Date
    Oct 2011
    Location
    Rumford, RI USA
    Posts
    1,187

    Quote 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 Images Attached Images
    Last edited by sfp1954; 02-16-2012 at 12:27 AM.

  4. #4
    ff Fortissimo sfp1954's Avatar
    Join Date
    Oct 2011
    Location
    Rumford, RI USA
    Posts
    1,187

  5. #5
    Moderator Brendon Wright's Avatar
    Join Date
    Sep 2008
    Location
    New Zealand
    Posts
    7,476

    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.

  6. #6
    Moderator Brendon Wright's Avatar
    Join Date
    Sep 2008
    Location
    New Zealand
    Posts
    7,476

    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.

  7. #7
    Moderator Brendon Wright's Avatar
    Join Date
    Sep 2008
    Location
    New Zealand
    Posts
    7,476

    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.

  8. #8
    Moderator Brendon Wright's Avatar
    Join Date
    Sep 2008
    Location
    New Zealand
    Posts
    7,476

    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.

Similar Threads

  1. Replies: 29
    Last Post: 09-15-2014, 04:18 PM
  2. M3 Octave Lowering
    By pspees in forum Hammond Organs
    Replies: 10
    Last Post: 04-05-2011, 08:09 PM
  3. digital 32' bottom octave - sound quality
    By pipe64' in forum General Chat
    Replies: 10
    Last Post: 06-04-2009, 12:57 PM
  4. WANTED: Bottom octave of a Rohr Schalmei
    By Don Furr in forum Buy & Sell Church & Classic Organs Archive
    Replies: 1
    Last Post: 11-16-2006, 08:57 PM

Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •