New M2, new questions!

[Shadow Giratina]

Hey all! I've recently become the proud owner of a new M2 which would be my first foray into tonewheelers. I do have some questions though. First things first, I want to chop it to make it much easier to get into my studio. I shouldn't have any problems with the woodwork or relocating the innards, however, I'm thinking I don't really need to keep the bass or expression pedal. I'm already going to hack out the speaker and run a line out into a guitar/bass amp so if I wanted a volume pedal, I assume I could get the same thing done with a volume pedal for a guitar. I also rarely use the bass pedals as is, so I don't think that the extra weight is worth it. Forgoing the lower half entirely would not only cut back on some of the weight, but then I could install some recessed handles into the sides and just drop it on one of those heavy-duty keyboard stands. I want to hear some people's feedback on that though.

Another thing is that percussion issue, which I'm sure most of you were prepared for just by reading the title. I've done some rough estimation and I believe that a Trek II is a bit more expensive than just getting an AO29 amp, percussion transformer, and the end cheek that I can just wire into the whole unit. That would also give me an AO14 that I can toy around with and maybe repurpose into a guitar amp (Hobbyist EE or really just a general amp tech.) I'm undecided though. I'm still not entirely sure a Trek II is compatible with an M2. I do know that instead of taking from a harmonic drawbar, I could just wire it into the bass pedal drawbar I plan on gutting though, right?

Speaking of amps, the amp that is installed now has a real bad issue with random bursts of noise, so some of those capacitors may need to be checked. I'm not sure about the tubes though. The whole unit is pretty dodgy and may need some sniffing around in.

On an unrelated note, the vibrato is motorboating, however, I checked the lugs with my multimeter and I'm not seeing any continuity on anything. I haven't checked the vibrato line box though, so perhaps a recap might need to be done?

[enor]

Many questions, I'll try to deal with them one by one.

1. Chopping. I don't really see what you're hoping to gain? If it's going to live in your studio, the footprint is the only dimension that really matters - and it'll be exactly the same whether it's in the nice looking stock cabinet or on a keyboard stand.

2. The expression pedal is more than just a volume pedal, it's also an eq pedal of sorts. As you back it off, the highs and mids roll off faster than the bass - it's sort of compensated for how the human ear hears. Just using a guitar volume pedal does not give the same effect at all, you'd be missing out on a big part of the tonewheel organ sound going that route. You certainly won't be acheiving the same thing as with the stock expression pedal.

3. Percussion. No you cannot use the pedal drawbar - for one thing, the pedal drawbar on an M-series only looks like the other drawbars when in fact it is not. It's connected to a variable capacitor in the back and the "drawbar" is just a linkage arm. But that's a moot point in this case as the perc unit doesn't send signal TO a drawbar, it derives signal FROM it. More specifically, it needs to steal a drawbar to use for triggering the percussion ping; and it needs to be a drawbar that's connected to a full length busbar in the keybed. Had this been an M-3, then the 9th drawbar is connected to a full length busbar, even though it doesn't have notes connected to the top portion. In the M-2, though, that's not the case. So in order to get percussion on ALL notes, you would have to sacrifice a lower drawbar to use for triggering. Trouble is, the 4th and the 5th are out of the picture since they are the frequencies actually being "percussed" so you can't steal those. That leaves you with the first three drawbars and I doubt you want to lose any one of those. Is there really no solution then? Yes, but it involves taking the keybed apart and installing a full length busbar in the 1' position, and adding a bunch of contacts. And if you're going to do that, it would be a shame not to install full foldback in the organ since everything is already taken apart.

3. Amps (and line outs). The M-2 has a field coil speaker, so you can't just remove the speaker - since the field coil also has the role of a choke in the amplifier's power supply section. You can disconnect the voice coil and hook that to a line out circuit, but the field coil MUST remain connected.

4. "Motorboating" can be due to a short to ground, but can also be caused by a break in the vibrato signal chain somewhere. A broken wire to the scanner, or an open coil in the line box, for example. Bad caps are unlikely to make it "motorboat", it tends to just make the vibrato shallow and unpronounced.

Good luck with your project! (And don't chop it) :)

[tiredoldgeezer]

1. It's your organ. Chop it if you want!

Hundreds, no! easily TENS of thousands of spinet Hammonds have been chopped, ripped, stripped, and incinerated. This sudden "Save The Whales" attitude for the spinet sometimes borders on virtue signalling - though probably not in this case. There's several chop-options to choose from with the most popular, naturally, being right at the generator shelf.

2. If you're going guitar signal - which many thousands before you have done - then that's all written up in a lot of places. Once your signal enters that chain, often complete with fuzz, phase, and chorus, no one will care about your volume pedal not being an adequate substitute for an expression pedal. And, of course, the Hammond expression pedal being a substitute for a pipe organ expression pedal that it was initially modeled after.

3. You certainly won't be the first to cannibalize spinets. Mix and match. It's been done many times.

3 (again). As the power amp isn't powering a speaker any longer, and you're doing that downstream with a guitar chain, the choke function of the old speaker isn't all that important. Besides, now you gotta field coil speaker which some designer guitar amp makers really like! If you score a newer AO29, it won't matter.

4. (should be 5). Couple of possibilities. One not mentioned is simply a puddle of oil that has seeped into the scanner. But that R&R is a bit involved.

[Shadow Giratina]

Addressing things in order, I probably should clarify that my studio is built into my house that's up a flight of stairs. The only thing keeping me from letting this thing live unchopped is because of that one reason. I *really* don't want to fight this thing up a whole 12 steps. Ridiculous, I know. The footprint I'm not concerned about, it's just an easier way of managing it. Ratchet straps and a dolly haven't failed me before though!

Yikes. Looks like I don't have much of a choice other than "cannibalizing" some M3 parts, as tiredoldgeezer put it so delicately. So the volume pedal is more of a tone knob on a guitar? Huh, I haven't noticed. I'm wondering if I can make a similar expression pedal by building almost a passive tonestack like what you'd find in a guitar! Perhaps a variable tone control pedal might interest more than just organists? I'll have to write that idea down. Maybe incorporate a no-load potentiometer in it so that you're totally bypassed at the maximum toe sweep point.

Oh wow, so the speaker is more than just a driver!? That's pretty weird. I haven't seen anything quite like that before. There are guides to converting it to a standard electrostatic speaker, so I imagine that I can do that and then do all my line out mods afterwards. Territory past that point appears to be pretty well documented about that, so I'm not all that concerned.

Thank you all for the input. I was expecting to be hit with a fair bit of criticism because I'm just some nerd with a soldering iron, but I can not articulate how helpful this info is, and I really appreciate it. Thanks for the info on the vibrato problem. I'll hopefully not have to dismantle the whole thing, but my fingers are crossed.


A question just popped up. So in the guitar amp world, when restoring vintage amps, it is near crucial to clip out the filter cap and replace the cord with a three-prong mains cable. There's so much info floating around about people modding the rest of the organ but nobody ever seems to talk about that. Is the amp unsafe as is with an ungrounded plug? I figure if I'm replacing electrolytics, I might as well for the safety of it but is it a big deal if not?

[enor]

Borrow a set of Roll-Or-Kari dollies and enlist a friend, and those 12 steps are a total non issue.

[tpappano]

I have been rewiring *all* my organs and Leslies with grounded power cords and connectors. My reasoning is that due to the age of the transformers and motors the possibility of insulation breakdown should be considered. Your amp chassis could become “hot” without you realizing it until you put your hand on it or connect some expensive piece of external equipment. With the M series organs you pretty much always have to replace the cord, might as well use a grounded one.

edit: I also add fuses

[tiredoldgeezer]

So the volume pedal is more of a tone knob on a guitar? Huh, I haven't noticed.

Not really.
Because the pipe organ used a set of shutters, and not volume, as such, there was a tonal change. Naturally, when shut, it would sound a bit more muffled.

Mechanically, Hammond used a set of parallel plates like a variable capacitor. However, at these frequencies and these levels, the capacitance aspect is considerably less, though still present.

This gave them what they wanted. An ever-so-slightly duller sound at low volume. The effect is a bit more subtle on a spinet than a console at some settings.

There are several schools of thought on the subject. Myself, especially when a partial-bus spinet is concerned, I think a volume ped is fine and dandy. The spinet was never designed for screaming highs and broad dynamics to begin with (but with some work can be made that way).

I find the volume pedal to be far more convenient and especially when playing a spinet without presets, noodling with the drawbars for just the right tone is all part of the process, anyway.

Regardless, your choice.

replace the cord with a three-prong mains cable.

Again, different schools of thought.

One says that more grounds is more safe. Yet another claims more grounds is more quiet. Yet another will point out that ACTUALLY there is no Ground, but simply a Hot and Neutral. Fine. Whatever you want. But there is a gotcha (isn't there always?)

While there is a chance, however remote, that a component could short to chassis, if the chassis just sits there, then no biggie (until you touch it with a wet hand because it's covered with shmutz and oil). I've touched one that i got a slight tingle from. I knew what it was from appliances of the same era doing the same thing. While a theoretical hazard, i don't know of any obituaries attributed to this specific condition unless you placed your bare foot on your amp and grabbed something grounded (which I guess is always possible).

But if that same chassis is connected to 3rd prong ground, upon shorting (from say a transformer leak) now there's current flow and possibly a LOT of current flow that can easily cause a fire (and has been blamed for such). At the very least, it'll let some magic smoke out.

Me, I don't "upgrade" to 3 prong. Been known to upgrade to heavy and polarized 2 prong while taking a bit of extra effort to search out which lead is the intended hot and which is the chassis ground or neutral. Been known to mount an IEC plug and just not connect the 3rd prong, too.

As many Leslies derive power from their hookup harness, you don't have much choice -- unless you plan to punch a new hole for a new cord... which has certainly been done. Guess what? Your choice.

[Shadow Giratina]

Hmm... I think that a three prong cable would be necessary if just for peace of mind. I know that you're not holding right on to a hot piece of ground like you would with a guitar, but the thought of the 1% chance of something being charged isn't the most comforting thing ever.

The good news is that I nabbed an M3 matching transformer, so there goes the easy part of this mod down! I'm not too worried about getting the cheek switches, however, I will definitely be saving up for an AO-29. It's funny, if you asked me why I was looking for an AO-29 amp a year ago, I would've said I was going to turn it into a guitar amp. Never did I think I'd be getting one for its actual purpose hahaha.

[Alek Z]

I have a spare AO-29 in my closet from an M100 I parted out, I snagged a resistor from it that I needed, and took the tubes. If you want, I'll send it to you for just the cost of shipping (no tubes, one resistor missing), PM me if you are interested

[joostovermars]

Yes definitely use a three prong power cord because you are connecting the line out to an external amp probably with a guitar cable probably with metal plugs. When something goes wrong in the organ there's a risk of full AC voltage on these plugs.

[Alek Z]

Here's my suggestion, chances are, won't be too long before an M3 pops up in your area for cheap and possibly free! Save yourself a truly unnecessary amount of hassle, and just do that. I found one for free 10 miles from me a week ago, and many more that are very far, just have some patience, check craigslist and Facebook marketplace daily, shouldn't take more than a couple months. Also, for the chop, whether it be your M2 or an M3 seriously don't do it. Get a friend to help and just lug it up the stairs, one at a time. I've done it before, it a not fun, but it's doable. And TRUST me, it's a hell of a lot less work than chopping. Chopping sounds great on paper, but you almost inevitably lose the expression pedal, you gotta move the amp around, you lose the internal speaker (which is not a great loss, but nice to have), rebuild the cabinet, and then make some kind of thing for it to sit on, which will look bad. Then after you've done all that, oh great! It's still over 200 pounds and only slightly easier to carry.

[Shadow Giratina]

Okay, I get it haha. I won't be chopping it then. That's just an excuse to fix the six other bass pedals that aren't functioning. Yay...

Alek, I may have fibbed about the title. To be honest, I nabbed this organ back in June, and after realizing it has no percussion, I just got a bit discouraged and it's been sitting in my shop taking up way too much room. I was going to look around for an M3 and possibly gut this M2, but it's been almost half a year now and the only M3 to pop up is being sold for $200 up in Maryland. I'm about 15 minutes from the border of North Carolina and VA, so that'd be quite the journey and I wouldn't trust taking an organ on a 200-mile road trip.

Either way, I have the prerequisite skills and I have no doubts about my ability to do this modification. I have a sneaking suspicion that the price of entry is going to be cheaper than any M3 that will pop up for sale in my area for the rest of the year. Also, c'mon, modifying and repairing these things is part of the fun of owning not just a spinet, but any instrument in general; That's at least how it seems here!

[enor]

You're absolutely right - working on them is a big big part of the fun!

What's wrong with the bass pedals? Describe the problem!

[Shadow Giratina]

Just some bass pedals that were working in the house that must've gotten damaged in transit to my place. I'll have to take a look at the wires and whatnot. I've heard that the bass pedals are usually the first thing to stop working on a spinet, so I hopefully will just have some wires to resolder in place.

[enor]

Are some of the pedals totally silent, or do they make a warbled sound (like the sound of two notes pressed at once)?

[Shadow Giratina]

They're just dead. No output at all. I didn't bother locking down the generator since it was a short drive and frankly speaking, I didn't have the room to do it in the house it was that cramped. Like I said, I'm sure a handful of wires got knocked around and need to be reattached. No big deal.