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Thread: '59 Hammond M3 Blond ~ Upper manual foldback + Lower manual lowering / bass mod

  1. #1
    pp Pianissimo mange656's Avatar
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    '59 Hammond M3 Blond ~ Upper manual foldback + Lower manual lowering / bass mod

    My '59 Blond M3 called Stella by my daughter was experiencing missing / static laden / weak notes and shifting the busbars didn't solve the problem. So I knew I was going to have to pull the manuals to get to the busbars. Since I have an L-102 hangar queen sitting in the garage I decided to do upper manual foldback while I had her apart. As I read about full foldback vs poor mans foldback I decided to do the full foldback. I skipped the manual tapering. I also added the lower manual bass mod where you drop the range of the lower manual by one octave.

    The results are fantastic. Wow the bass really kicks. Playing the 16' + 1' registration is good ALL THE WAY UP!! What a difference in the overall tone. I don't know that I want to do another foldback mod due to how labor intensive it is but I had the time I the results were worth my effort. I will have to record the results and post them.

    One advantage of going into the M3 as deep as I did is that I was able to clean places that hadn't seen any cleaning since she was built. Man I had a dryer lint screen worth of lint under both keybeds. Absolutely filthy. So now she is all clean. The electrolytic caps have been replaced, the power cord too. I found the perfect combo of tubes to get a nice sound.... RCA for the 6au6, 6ba6, 6c4 and 5u4gb tubes, Sylvania for the 12au7, 12ax7 and 6v6 tubes. Nice, real nice. The M3 feeds a homebuilt Leslie 147 sized cabinet with a Jensen V21 driver (16 ohms) and a Weber 15F200 (Jensen C15 clone)(8 ohms) homebuilt crossover adapted to 8 ohm woofer and 16 ohm mid / high frequency driver all powered by a Leslie 25 amp. Yeah I know it is only a 20 watt amp but it cranks. Besides 20 watts vs 40 watts is only a 3db difference in spl. Bass is solid and doesn't fart out as I thought it might.

    If you are thinking about these mods:

    Upper manual foldback: Lots of time robbing the L-102 for contacts and busbars (had to make a small mod to those). Lots of time installing the new contacts. Organ down for a week. Real improvement in sound when using four highest drawbars.

    Lower manual bass mod: Much easier and a real improvement in sound. Less than a day to complete. I left the first 12 wires at stock length and extended the other wires. I installed jumper wires from 1 to 13, 2 to 14 ... 12 -24 on the terminal strip. The extended wires start on terminal 25. By doing it this way the original wiring harness can be restored to stock by removing the jumpers and I didn't stress the wiring harness by trying to get more length out of it.

    Thanks

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    ff Fortissimo torea's Avatar
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    Cool! Glad it worked out well for you!

    So you removed the manuals completely? I would think that'd make a lot of it a lot easier, I know harvesting contacts is a lot easier when the manuals can be shifted around. I'm thinking of doing something to our M-111, most likely the lower manual mod. Upper foldback would probably be nice, but is a ton of work, and the organ sounds great through a 31H anyway. I'm still on the fence. Maybe if I get bored I'll do full foldback up top and the lower mod at the same time.

    Which instructions did you use for the lower manual mod? I keep confusing myself as to what I'd actually be doing, I think I just need to read Brendon's files again.

  3. #3
    pp Pianissimo mange656's Avatar
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    Quote Originally Posted by torea View Post

    Which instructions did you use for the lower manual mod? I keep confusing myself as to what I'd actually be doing, I think I just need to read Brendon's files again.
    I used Brendon's files with some minor differences. Since I am an electronics technician by trade and have done complete overhauls on equipment including rebuilding wiring harnesses I elected to alter the install to make it more friendly to the wiring harness and wire / cable strain. With the lower manual out and on the bench I soldered jumper wires to terminals 13-24. Those wires were long enough to reach back 12 terminals lower ie 13 went to 1, 14 went to 2, all the way up to 24 which went to 12. When I soldered them in I only soldered them to terminals 13-24. For the connections to terminals 1-12 I made sure to crimp the jumper wire with needle nose pliers so I could insert the original wire for that terminal and then solder both together at the same time when I installed the lower manual back into the organ. I extended the block of wires by soldering a short extension onto the original wire and heat shrink tubing the joint. (a hair dryer / blow dryer works if you don't have a heat gun). There are 74 terminals on the lower manual of an M3. The first 12 are connected as they originally were. The next 12 terminals 13-24 are connected one for one to the 12th terminal lower (thats how you get 13 connect to 1, 14 connects to 2, 14 connects to 3 until you get to 24 connects to 12. That takes care of the foldback for the first octave of the lower manual. The wiring harness wires from 13 to 62 were extended with per the reference above to allow them to reach 12 terminals higher then they would normally connect to. That means wiring harness wire 13 connects to terminal 25, wiring harness wire connects to terminal 26 ..... on up. You will have 12 wires in the harness that do not connect to anything when the job is done. Those wires would be 63-74. I just covered the end with heat shrink tubing.

    Why go through this trouble? Well this keeps the wiring harness strain and routing exactly as it was from the factory. The process can be reversed. I bent the stripped end of each wiring harness wire and the end of the extension wire into a U shape and that allowed me to connect them and solder them together in a manner that could be easily reversed. As an added benefit the extended length of the harness allowed me to set the lower manual on a board with the keys pointing at the ceiling and sit down and solder. Much nicer than getting under the organ to solder. I worked right to left (from terminal 74 down to terminal 25). Then I skipped terminals 13 to 24 (they are jumped to their counterpart in terminals 1-12) and soldered in the wiring harness wires to the correct terminal for 1-12 again working right to left. I used a jumper lead to extend each drawbar wire to a lower manual drawbar to ensure each key sounded correctly at the correct location. I had one cold solder joint that was easily repaired by soldering the joint again.

    Yes I pulled all the keys and cleaned them as well as under them. Cleaned the busbars and corrected any other problems I found. If you search ebay for hammond foldback kit the guy has documents that show you how to do it including really good pictures of the guts of a representative organ.

    I can add some additional information or send files if you still have questions.

    Thanks

  4. #4
    ff Fortissimo torea's Avatar
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    Thanks for the details. Don't suppose you have any pictures? I've torn apart an A-100 for a busbar cleaning, and an M-2 to get the contacts, but I like to see what I should be doing before I go off and make it backwards

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    pp Pianissimo mange656's Avatar
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    Hammond M3 Lower Manual Bass Mod Pictures

    Here are some pictures of the mod. The first photo shows the start of the terminal strip and wiring harness. The next photo shows the jumpers added to extend the wires. The third photo is a closer view of the jumpers between terminals 1-24.

    With my version of the mod you cant tell that it has been done because the wiring harness has not been rerouted or pulled tight to gain length under the manual.

    Basic idea: move each wire of the wiring harness 12 terminals (one octave to the right). That means we connect the left most wire in the wiring harness to terminal 13 and continue connecting from there. Since the lowest 12 terminals are no longer connected to anything we jumper them to repeat (foldback) the frequency one octave above.

    Electrically:

    Terminal 1 jumped to terminal 13 and connected to the wiring harness wire #1

    Terminal 2 jumped to terminal 14 and connected to the wiring harness wire #2

    Terminal 3 jumped to terminal 15 and connected to the wiring harness wire #3

    Terminal 4 jumped to terminal 16 and connected to the wiring harness wire #4

    Terminal 5 jumped to terminal 17 and connected to the wiring harness wire #5

    Terminal 8 jumped to terminal 18 and connected to the wiring harness wire #6

    Terminal 7 jumped to terminal 19 and connected to the wiring harness wire #7

    Terminal 8 jumped to terminal 20 and connected to the wiring harness wire #8

    Terminal 9 jumped to terminal 21 and connected to the wiring harness wire #9

    Terminal 10 jumped to terminal 22 and connected to the wiring harness wire #10

    Terminal 11 jumped to terminal 23 and connected to the wiring harness wire #11

    Terminal 12 jumped to terminal 24 and connected to the wiring harness wire #12

    Stop. At this point we have wired terminals 1 to 24 using wiring harness wires 1-12 and jumper wires. If you start with low F on the lower manual with what was the 8' drawbar the left most F = Frequency 18. If you run a chromatic scale F, F#, G, Ab, A, Bb, B, C, C#, D, Eb, E function normally. The next F drops back to Frequency 18 because we jumped terminal one to terminal 13. The result is the second lowest octave using the former 8' drawbar is a repeat of the first (lowest) octave.

    Since we stopped with terminal 24 above we need to finish wiring the manual. We continue this effort with terminal 25.

    Terminal 25 connected to wiring harness wire #13

    Terminal 26 connected to wiring harness wire #14

    Terminal 27 connected to wiring harness wire #15

    Terminal 28 connected to wiring harness wire #16

    Terminal 29 connected to wiring harness wire #17

    Terminal 30 connected to wiring harness wire #18

    This continues to the right until we have connected wires to all the terminals.

    There are 74 terminals and 74 wiring harness wires. Since we did a bass foldback to the lower manual only 12 wiring harness wires were required to cover the first 24 terminals. That means we will have 12 non connected wiring harness wires at the end of the harness. Those would be the wires 63-74 which would have been connected to terminals 63-74 originally before this modification. You will need to make sure the ends don't short out against the chassis or loss of tones will occur.

    My extension of the wires was for durability and longevity of this modification. The harness wires connect to the same terminals in the upper manual. The upper manual is fed from the TWG (ToneWheel Generator). We all know what happens if you don't lock down the TWG and transport the organ. Potential broken wires and missing frequencies. Why would I want to put additional strain on the wiring harness that goes to the TWG and upper manual just to save an hour of work. Long term reliability is key. If one of my extender wires fails I can easily get to it without tearing the organ apart to the degree I did for this install and repair it. Not so If I break wires in the harness, upper manual or even TWG.

    The lower manual first three drawbars are now 16', 8', and 51/3'. I swapped the wires for the 8' and 5 1/3' drawbars so my first three on the lower manual are now 16', 5 1/3', 8'. Let me know if I have totally confused you.

    Hope this helps

    Mange
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    pp Pianissimo mikey383's Avatar
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    I'm still working on doing the foldback on my M3. I removed the manuals completely and laid them on my bench to do the mods. I thought about doing the lowering mod, but didn't.

    Actually, it's more of a pain than my '64 M103 was, because of the bakelite retainer holding the key actuators in place. I got it all done and put back together, fired it up, and had a constant tone on one drawbar on each manual, and one missing note on each manual, so I had to take it all back apart. I found that when I inserted the contacts, one on each manual went under the busbar instead of on top. Got those squared away, and it's now ready to be put back together....but I just got home from work and it'll probably end up waiting until tomorrow.

    I did the manual tapering on the upper manual while I was in there, but decided not to do the lowering mod just yet. With all the info you gave, I just may do that tomorrow when I get this thing put back together.
    '53 Hammond C2 w/JR20 tone cab
    '57 Hammond M3 w/'64 Leslie 125

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    pp Pianissimo mange656's Avatar
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    My favorite part / result of extending the wires on the lower manual wiring harness is that I was able to put a piece of 1/2" plywood under the upper manual and over the front of the organ and the extended wires were long enough to put the lower manual on the plywood keys pointing at the sky and pressed against the front of the upper manual and sit and solder the wires into place. A 6' jumper wire with insulated alligator clips was used to test the mod before bolting every thing in place. I just connected the lowest drawbar to each busbar and checked out each key to ensure it sounded. Worked great. There is now way I would go back to a normal lower manual. Before I started playing Hammond I was a bass player and man oh man I really locked into the new bottom end my M3 has. Or as my daughter says "Stella has a big ole booty bottom now" (Stella is the 59 M3's name wife and daughter view her as "the other woman").

    This mod + upper manual foldback rocks!

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    mp Mezzo-Piano Tubejack's Avatar
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    Quote Originally Posted by mange656 View Post
    I used Brendon's files with some minor differences.
    Where are those files located?

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    ff Fortissimo torea's Avatar
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    Quote Originally Posted by Tubejack View Post
    Where are those files located?

    Send him a PM. He's got a ton of Word, PDF, picture files, etc. He'll email them to you

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    Moderator Brendon Wright's Avatar
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    Hi Guys!
    Sorry I haven't been lurking much lately... Work's keeping me busy. Since it's Monday, I'm pretending there isn't any work until after lunch.
    Tubejack, you can email me at brendon(at)wright(dot)org(dot)nz and I'll forward the whole lot your way.

    There's also a Kon Zissis recipe for filtering pedal tones to the LM so they're clean like the rest...

    My work's in Illustration/cartooning and a cupla years back I WAS planning on writing a book on the foldback thing but didn't do it SOON enough, I didn't put everything down in writing as I went, just took a ton of photos. I could lay the book out and produce the pdf, but the text would need either written by someone else OR I'd need notes from half a dozen people on how their job went, tips and tricks, and someone like Mange who's got a background in electronics would be a whole lot more sympathetic to all manner of things inside the organ.

    There've been enough guys now doing M's L's and T's to cover the whole process on all three kinds of spinets. (and hopefully taken photos)

    Does anyone like the idea of reviving the book idea?
    Want to write up the text?
    Want to provide notes for me or someone to refer to for the text?

    It's conceivable we could make a gallery here with all of the files, charts, notes etc necessary and leave them for someone else to write up after we're gone!
    -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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