PROJECT M3 - How I Spent My Summer Vacation

[Rusty Mike]

INTRODUCTION

About a year and a half ago, I picked up a 1956 Hammond M3 from fellow KC'er JoeP. Joe was essentially looking to clean his house a bit, and the only price I paid was the effort to come an pick the thing up from his house. A couple of friends and a pickup truck later, and it was in my basement.

 

To me, it was an opportunity to not only own a vintage Hammond, but also to learn about it. I wanted to better understand how to clean it, fix it, maintain it and play it. I have no pressure to do anything with this instrument, as well as no real budget to speak of. The plan was to fix and enhance as I found spare cash and time.

 

While I don't know its exact history, the organ has been gigged with quite a bit, and is cosmetically beat up. It was mostly functional when I got it from Joe, but had a few issues. It had one non-functioning drawbar (easily fixed), a Leslie 26-1 box with two broken switches and, most significant to me, percussion that was not working. I did some research through the Organ Forum and other online repositories, tinkered a bit, and came to the conclusion that I did not have the experience to fix the percussion.

 

Once of things I tried was to buy another AO-29 amp from eBay and replace the original amp. That attempt failed, as the amp was from an M-100, and the wires on the output stage of the amp melted as soon as I fired it up. I think it might be because the M-100 used a magnet speaker and the M3 has a field coil, which have different power and load characteristics, but I'm not sure about that one. So I pulled the M-100 amp out pondered for a few months.

 

While tossing my coins in a jar to get a qualified technician to look at it, I cleaned it up a bit. Since I don't ever think I'll own a Leslie amp (more on that later), I removed the 26-1 kit and all the associated wiring. This past March, I contacted Paul Studer from the Organ Service Company of NJ to help. Paul worked at the original Hammond factory in Illinois years ago, has a deep knowledge and a great reputation. Paul is 82 years old, and is not afraid to tell you that constantly. He drives a minivan loaded with manuals, tools and parts, and is constantly talking about one thing or another. The funny thing is that you don't really hire Paul to work on your stuff as much as you pay to be his apprentice for a few hours. You carry stuff for him, help him up and down the stairs, help him solder and fetch stuff for him. Overall, a very sweet man. I didn't want to stray too far away, since he always had something valuable to say. He took both amps back to his shop and returned a few day later with both amps functioning perfectly. Paul fixed the percussion section of the original amp, upgraded some of the capacitors, and fixed the fried M-100 amp. He dropped the original back in the M3 and it all worked great.

 

Since Paul put it back into playing condition, I've been thinking for the past few months about what else I wanted to do to this. Paul tested the tone generator capacitors and showed me the extreme drift of the older brown paper caps, which inspired me to consider a total cap replacement. I knew I wanted to put a rotary sim on it at some point, so a line out kit was on the agenda. I also read about other M3 modifications, and decided to take on a few challenges, like doing some foldback work on the upper and lower manuals. So I saved a few more nickels and started planning my summer vacation.

 

I took off the last week of August since I had time coming. Since we had no actual vacation plans, I decided to spend the time working on the M3. I contacted Paul again and arranged to buy a full set of capacitors from him, hoping I could also pick his brains about the other projects. I stopped at his shop the Friday before my vacation week to pick the parts up, and Paul has all the parts ready, but tries to talk me out of doing the capacitor replacement due to the amount of work. I told him I want to push forward and he agrees to sell me the parts. Using the schematics and an old M3 filter board, he walked me though the complete process. He even gave me the old board to take home and use for guidance and parts.

 

The Internet had enough information about the foldback projects, and since I didn't buy any parts from Paul for this, I didn't want to bug him about it. I did buy a Trek II OBL-2 line out kit from him, and wanted to ask him how to install a switch that would allow me to cut off the internal speaker when I only wanted to the hear the line. I was concerned that simply turning off the speaker would remove the 8 Ohm load the amplifier needed to see to operate properly, so I wanted the switch to incorporate a resistor in place of the speaker. Paul scratched out a sketch, tossed a resistor in the bag and wished me well.

 

The next several posts describe this week's projects.

[mate stubb]

:snax:

[Rusty Mike]

PROJECT 1: TG Capacitor Replacement

 

Despite Paul Studer's warnings, I decided to move ahead with this project. I wanted to get the tone generator chassis in a better position, so I removed the springs and guide bars from it, pulled it forward and placed some wood blocks in the back to tilt it toward me. I first replaced filters 44 through 49, as they originally had no capacitors, and used a different types of filters than the rest, and Paul was kind enough to build these little circuits for me. These were also in the back, and a bit harder to reach, so I wanted to get some of the tougher ones out of the way. Here's a picture of the one of the installed filters:

 

 

After those five were done, I worked right to left, alternating between the back and front. I first started by positioning the caps over the transformers, but then changed my mind midway through and positioned them instead over the middle area where the original caps sat. Every few replacements, I turned the organ on and tested at various drawbars and keys to make sure I wasn't screwing up. Here are some pictures of the completed replacement:

 

 

 

 

Fortunately it all worked out well. I'm very happy with the quality of the sound.

[Rusty Mike]

PROJECT 2: Drawbar Repairs

 

This one was kind of a quickie. I had a few things I needed to fix:

• Replace the 1 Ohm resistor on the lower manual fundamental drawbar
  
• Swap the upper manual 5 3/8 drawbar with a lesser used one. The drawbar was missing the little guide rails, and had a very different feel from the surrounding drawbars. Since this was one I used a lot, I wanted to swap in one that still had the guide rails. I changed this with the top drawbar of the lower manual, but broke the 1 Ohm wire when making the swap. Since I didn't have another resistor, I simply replaced the wire with a copper jumper wire, which seemed to do the trick
  

Sorry, no pics. There's nothing sexy about drawbar repairs.

 

PROJECT 3: Poorman's Foldback

The M3 doesn't have any foldback. This means that the upper harmonics simply stop at a particular note. This negatively impacts the vibrancy and scream the M3 can produce. There is a way to install full foldback by robbing busbars from other organs and installing them in the M3. I opted to do the poorman's foldback, which adds foldback to only the 1' harmonic to the upper 18 keys, and requires no additional parts. I got instructions for this from the Organ Forum.

 

There are a bundle of wires just connected to ground on the upper manual that are snipped and resoldered to other terminals. The operation itself is rather simple, challenged by the small, awkward space to work in, the really tiny wires and difficulty getting sufficient lighting. Pictures:

 

 

 

It works great. Even with just the organ's vibrato, you get that nice shimmer in the upper keys. I'm really looking forward to getting a rotary sim connected up!

[Rusty Mike]

PROJECT 4: Lower Manual Modifications

Once the upper manual foldback was done, I moved on to the lower manual modification. I read on the Organ Forum where someone lowered the lower manual to enable a much better left hand bass capability. This task entailed clipping the wires from the upper 12 lower manual terminals, jumping wires from terminal 1 to 13, 2 to 14, etc. and moving the remaining wires up 12 terminals. This lowers the entire manual one octave, so the keys line up exactly with the upper manual at the same footings. It also folds back the fundamental drawbar so it acts more as a sub-fundamental, and folds back on the lowest octave.

 

This picture shows the jumpers I soldered to terminals 1 12:

 

This pic shows the completed job, with the jumpers in place and the top 12 wires capped off:

 

This is a closeup of jumpers tucked under the terminals:

 

The modification sounds great. The low end is nice a beefy, and I can walk bass lines with my left hand.

[Rusty Mike]

PROJECT 5: Line Out

Like I said in my intro, I conferred with Paul Studer about properly connecting the OBL-2 kit, as well as got some guidance about creating a proper speaker cutoff switch that maintained the proper load to the amplifier. I fabricated a frame out of a piece of aluminum, and connected up some multi-core cable.

 

Here's a picture of the switch assembly:

 

 

These pictures show the mounting of the switch, OBL-2 and wiring connected to the M3, and termination of wires at the speaker:

 

 

 

The only mistake I made was labeling the framing on the switch. ON is actually labeled as OFF right now, so I need to fabricate some kind of cover showing the right way. I can't really flip the switch over because of the offset.

 

So why did I pick the OBL-2 with a 1/4 line out and not another Leslie kit? Mostly because I don't ever expect to have a Leslie amp in my house. I don't have the budget, I don't have the space and I can't sneak it into the house past my wife's nose. I'm much more inclined to get a Leslie simulator; I plan on ordering the GSI Burn as soon as it's available. It would suit me better than a Vent, since it has other effects, such as reverb, which make it more suitable than a Ventilator. I can also use the Burn on my PC361 as well, so it will get plenty of use.

 

Maybe, someday, in a few years, I'll look into the new Studio 12 or a 2101, as they suit my studio space.

[Rusty Mike]

THE FUTURE

 

At this point, I'm happy with the inner workings, I'm looking forward to putting a Burn on this and bringing it to life. It's still kind of crummy looking, but, like Han Solo once said She may not look like much, but she's got it where it counts. The wife wants me to do some kind of cosmetic upgrade to this thing, although I'm not at all bothered by how it looks. Paul Studer did some research for me, and got a price of $1,000 to repair and refinish. Given that the M3 wouldn't fetch more than a few hundred dollars (and I'm already about $600 invested), it's hard to justify it. I could do some of the work myself, but I'd have to move it out of the basement and spend a lot of time doing something I'm not sure I can do that well.

 

I plan to build a cover for the back to pretty it up a bit. Just a simple wooden frame with a material cover attached by Velcro. That will be a simple project.

 

I'm considering some kind of wooden cover for the pedals, more to serve as a place to put my foot or an effect pedal when I'm not learning bass pedals. I'm also thinking about building a replacement music desk and/or simple wooden frame to place another keyboard on top with a slight tilt.

 

For now, I just want to play and enjoy this instrument.

[J. Dan]

The only mistake I made was labeling the framing on the switch. ON is actually labeled as OFF right now, so I need to fabricate some kind of cover showing the right way. I can't really flip the switch over because of the offset.

 

I bet the metal tag from THIS toggle switch would fit the one already installed and cover the existing labels. (if not, maybe you could use the linked toggle switch instead?)

[mate stubb]

 

Great work! I never heard of the poor man's foldback trick, great to know.

[eric]

Excellent documentary! Thanks for sharing.

[Kawai James]

Great work, thanks for sharing your progress!

 

James

x

[Markyboard]

That looks like a tremendous amount of work - you must have a lot of patience and good eyesight. I need to do a bit of work on my B3 including a dual Leslie refurb. Nothing close to the extent that you've done here. And even still I keep puting it off due to other projects. Nicely done - congrats.

[Rusty Mike]

Patience, yes. Eyesight, not so much. A big challenge was keeping sufficient lighting in those tight little spaces. I also had to keep taking my glasses off for the real close up work.

 

And sitting on the floor for extended periods of time isn't the roll in the hay it used to be either!

 

Dan, I appreciate your suggestion about the switch. I really just need to either flip the connections on the back of the existing switch or relabel the front.

[Outkaster]

Paul has one of the largest collections of parts and inventories also from what I understand.

[WesG]

Great thread! I'm in the middle of a similar project.

 

Switch label - try wiping the ink off with rubbing alcohol. Alternatively, switch the wires around on the switch..

 

Finish - try Howard's Restor-a-finish from Home Depot

 

Back - I made one for my L111 gigging organ out of 3/16" plywood. I had to add a fan to exhaust the air from the tube amp. An alternative would be to drill a bunch of holes with a hole saw in a decorative pattern near the top and bottom, to set up convection. The factory back (rare) is similar to an A100, basically, a tic-tac-toe frame covered with speaker grille cloth.

 

Lower drawbars - the top and bottom line up properly in stock configuration; push in the top manual's brown drawbars and they will make the same notes. Now you have it so that 8888 and 8888 sound the same, which is not quite the same thing -- try 8400 and see what I mean.

 

Foot pedal cover - are you using a proper organ bench? It sounds like you may not be high enough. Organ benches are 21" high. I have a 34" inseam and do not accidentally hit pedal tones.

 

Tilt - what I do for my organs is I remove the music desk and put a couple of blocks at the rear. The blocks are made from rough-cut 1x4 and covered in toolbox drawer liner. This keeps the upper keyboard stable, and tilted forward just enough that I can play it comfortably while seated...but can still play it properly when I stand up.

 

Wes

[Joe Muscara]

[Rusty Mike]

Paul has one of the largest collections of parts and inventories also from what I understand.

 

His shop is in the garage of his home. He had a couple of B's waiting for repair and one in process. He took me into his basement, which had a fair number of parts, but was not a cluttered mess at all. He also has a shed with a whole bunch of other parts. His shop had lot of drawers and little bins and such, so he seems to have a lot of stuff.

 

I was talking to him about my starter motor, and he told me a story about recently working on one of Springsteen's B's and the odd problem the starter had. He wasn't necessarily name dropping, but was rather casual about it.

 

Paul even called me yesterday to see how my projects went. I can't speak highly enough about him.

[Rusty Mike]

Wes, thanks for the pointers. I'll try the alcohol and see if it will erase the Sharpie lettering.

 

For the back, I had something in mind with speaker grille cloth or some other material. I'd like to allow air flow. I won't be gigging out with this, so it's more about aesthetics than protection.

 

The foot pedal cover is more for a place to put my foot, Kind of like the dead pedal in a car. I also thought it might work as a resting place for effects pedals. I should check the height of my bench, though, as I do get some leg fatigue when I try to play pedals.

 

Using your tilt approach, do you have issues with the top keyboard sliding forward, or is the tilt not extreme enough?

 

Thanks

[WesG]

My tilt is not extreme enough for the top board to slide forward, and there is a little "lip" for the music desk which I can align with a cavity or protrusion on most boards to make it even more stable. I had a singer with a bad habit of leaning his hand on the piano, and he never once managed to push it off, either....the drawer liner really adds a lot of friction!

 

Wes

[Outkaster]

Paul has one of the largest collections of parts and inventories also from what I understand.

 

His shop is in the garage of his home. He had a couple of B's waiting for repair and one in process. He took me into his basement, which had a fair number of parts, but was not a cluttered mess at all. He also has a shed with a whole bunch of other parts. His shop had lot of drawers and little bins and such, so he seems to have a lot of stuff.

 

I was talking to him about my starter motor, and he told me a story about recently working on one of Springsteen's B's and the odd problem the starter had. He wasn't necessarily name dropping, but was rather casual about it.

 

Paul even called me yesterday to see how my projects went. I can't speak highly enough about him.

 

Yes one of the B-3's Danny played and now Charlie does. The other is a back up if it's the ones they are using on the road. I know another tech in NJ that has ties into that camp actually. Small world I guess.

[JeffLearman]

Three thumbs up

[Joe P]

Hey Mike,

 

Great to see you got the M3 humming. I bought it from a guy in Jersey City in 1987 along with a 44W, humped both out of his basement onto a High Railer and that's where it all began!

 

I'm glad to see that it will continue to make music and bring enjoyment.

 

Regards,

Joe

[ITGITC]

Three thumbs up

 

I'm not even going to ask about that third thumb.

 

Yeah... That's what she said!

 

 

 

[Rusty Mike]

Hey Mike,

 

Great to see you got the M3 humming. I bought it from a guy in Jersey City in 1987 along with a 44W, humped both out of his basement onto a High Railer and that's where it all began!

 

I'm glad to see that it will continue to make music and bring enjoyment.

 

Regards,

Joe

 

Joe! That must have been a sight to see!

 

Yea, the old girl is cleaning up nicely. I'm having a lot of fun playing and tinkering.

 

Thanks again.

[Skinny]

Mike,

 

This is all very cool. Glad to see some love for the M3. My first Hammond that I bought 10 years ago was an M3, and I still have it (it currently resides in my parent's basement; no room for it in my current house). I used to run it through a Pro3tm. As a then 23-year-old who had never touched a console, I thought I was in heaven.

 

I would love to fire it up and do some mods, but I don't have the time, nor the knowledge. Adding foldback to my M3 is something I've always wanted to do.

 

Yes, I have my C2/122 in my house, and it is amazing, but I will always have a place in my heart for the M3. In the near future when my wife and I buy a new house, I hope to have the space for it again. (Actually, I have a T-212 as well, but I could take or leave that one).

 

Anyway, it's great to see the "underdog" Hammonds getting some love. Yes, consoles are wonderful, but some spinets ain't too bad, either. Nice job.

 

 

[wmp]

Very cool thread! Thanks for sharing.

 

I didn't know about the poor man's foldback or that installing full length buss bars was possible for full foldback.

 

I like M3s and M100s a lot.

[WesG]

wmp, you need full length buss bars AND key contacts. The reason they are already in place for the 1' drawbar is that they are already used to trigger the percussion.

[opdigits]

It's fun and interesting to read play-by-play reports like this! Kinda feels like I'm right there in the workshop with you.

 

Thanks Rusty Mike!

[WesG]

BTW, do you have any details on the filters you added for tones 44-49?

[Idemfred]

Hi,

 

just got an M3, doing the lower manual mod with jumpers mean that 2 first octave will be the same? BTW you work really well.