Crumar Mojo Review - Gig Tested

[WheelHead]

I've been thinking about tinkering with the action to make it more Hammond-like.

 

It has about 1/8" too deep a throw, which might not be too hard to change. I would need to verify that it doesn't affect the velocity triggering when turned on.

 

And a slightly less stiff set of springs should finish it off nicely. I have no idea if these are available.

 

Just measured mine kind of crudely with a chopstick and using my thumbnail over the next key depressing one key before it flexes. On numerous reads on both upper and lower it is slightly less than 7/16" by about 1/32'. This does not have velocity to the best of my knowledge. (this is MK1 not MK2)

 

W.

[Joe Muscara]

[video:youtube]http://www.youtube.com/watch?v=6cLseymoLJI

[Jim Alfredson]

I don't understand how that measuring process takes into account the leakage or the actual tone of each tonewheel due to it's pickup capacitor?

 

One thing I noticed when programming my custom tonewheel sets on the XK3 is that, depending on the model of the organ (C2 vs B3 vs A100 for example) and the vintage (1954 vs 1958 vs 1974), the actual harmonics involved in the leakage per tonewheel and the level of those individual harmonics are different from organ to organ. It seems to me that the only thing the measurement in the video is measuring is the output in millivolts of the tonewheel itself, not how bright or dark it is tonally, or the crosstalk / leakage.

[Joe Muscara]

Thanks for those comments, Jim. I was wondering the same thing myself. It's not that these "measured" organs sound bad, and apparently measuring them does give different results from organ to organ, but there does seem to be nuances it doesn't get.

[AnotherScott]

It seems to me that the only thing the measurement in the video is measuring is the output in millivolts of the tonewheel itself, not how bright or dark it is tonally, or the crosstalk / leakage.

The question is, then, what mechanism is it in a tonewheel organ that makes one model sound brighter or darker, or gives a different character to its crosstalk or leakage. Is it possible that, for some of these things, it is in fact related to the outputs levels of the different tonewheels? For example, maybe organs that have lower output on the higher tonewheels are the models that sound darker? Or models that have higher output on certain tonewheels contribute more crosstalk or leakage at their associated frequencies?

[Craig MacDonald]

It seems to me that the only thing the measurement in the video is measuring is the output in millivolts of the tonewheel itself, not how bright or dark it is tonally, or the crosstalk / leakage.

The question is, then, what mechanism is it in a tonewheel organ that makes one model sound brighter or darker, or gives a different character to its crosstalk or leakage. Is it possible that, for some of these things, it is in fact related to the outputs levels of the different tonewheels? For example, maybe organs that have lower output on the higher tonewheels are the models that sound darker? Or models that have higher output on certain tonewheels contribute more crosstalk or leakage at their associated frequencies?

 

I expect that B3-er is right in that the height of the wave simply represents the overall level/voltage of the wave.. HOWEVER, since the crosstalk/leakage is in fact other tonewheels signals acting on this wave (albiet subtley) the wave is not a true sine wave.. If you look at the wave it is thick and fuzzy rather than thin and smooth.. I expect that if you expanded and looked closely at the wave you would see that it is not clean and true (as it would be if it were one tonewheel being measured in isolation).

 

I think that the affect of the crosstalk/leakage is evident, but it has nothing to do with the height of the wave, but rather the actual shape of the wave. When you look at the wave on this scope, the wave itself looks fuzzy (which I believe is the result of crosstalk/leakage) but it's not obvious because of the scale thats being used on this scope. If you were to look at one wave in isolation, and blow it up, I bet you can see it more clearly that the individual wave is not true, and that is the crosstalk/leakage (which is simply other waves subtely acting on this wave). Based on my understanding of additive synthesis, this is exactly what I would expect to see in this scenario, a fuzzy wave. I suspect that this fuzziness is one component of the overall tonal colouration (beyond the obvious primary tone).

 

BTW I could be entirely wrong, and the fuzziness could be simply the nature of how this scope works and displays information, but if you think about it, crosstalk and leakage is really other tones/waves that are acting on the primary wave, which I would expect would show on a scope like this as a fuzzy or jagged edged wave.

[Joe Muscara]

Sure, Craig, but the question is, how is that "fuzziness" (assuming that is the crosstalk/leakage) being modeled? The only thing that gets input into VB3 is the height of the wave.

 

Unless the fuzziness of wave Y is due to the amplitude of waves X and Z on either side or something.

 

I guess we can speculate all day. What we really need is a post from ZioGuido.

[ZioGuido]

This kind of measurement only takes into account the amplitude of each tonewheel before this is fed into the rest of the circuit. This is important for the "character" of the organ, and helps the simulation software to recreate the overall organ sound, but doesn't take into consideration the rest of the sound. Crosstalk is only partially present at the generator's outputs. Unfortunately there's no way to "measure" the total crosstalk and leakage of an organ, those can only be measured by ear.

 

By the way, if you make a cable with a TS jack on one end and a female BNC on the other end and use it to connect the probe to an amplifier in order to hear each wheel before it goes trough the rest of the circuit, you can hear the part of crosstalk that is present in the generator already. This of course affects the way the total crosstalk sounds like at the organ's output.

 

Also, the crosstalk inside the generator is influenced by each single tonewheel amplitude. For example, if you have a high volume on wheel n. 61, this will be more present on wheel n.13 as well, since they are mounted into the same "chamber".

 

 

[Craig MacDonald]

Joe, yes I would think that it's the tonewheels situated side by side that have the most affect on each other (and if I recall correctly I think Hammond actually changed the order of tonewheels in different generations of the tonewheel generator to reduce the crosstalk/leakage affect), but they also built in filter/capacitor circuits to reduce this affect as well. The relative voltages of each of the tonewheels does, for the most part, determine the tone colour, but this is also affected by the filter/capacitors circuits. My point really was simply to point out I thought the crosstalk/leakage was evident on the signal in the video.

 

I can't speak to how Guido models this in VB3 but I know that he does go to great lengths to realistically recreate all elements of the hammond sound. I'm a big VB3 fan.. and have been for years!

 

[MoodyBluesKeys]

Amplitude of each tonewheel is only one of a number of parameters. The factory setting was done by moving the magnetic pickup and varying the distance from the actual wheel.

 

The tonewheels themselves do not produce a perfect sine wave even with the filtering in the generator. The tonewheel itself has teeth cut in it that produce a very rough approximation of a sine wave. Then, each individual tonewheel note has a formant filter - in some cases it is resistive/capactive, others inductance and capacitance, some just inductance. EACH of the old tonewheel generators when new was balanced to Hammond specifications by an employee, this was done by custom varying the values of parts used. Over the years, the company used different master paramenters for what the instrument "should" sound like.

 

All of these components, especially the resistors and capacitors, are subject to variation over time in their value. So, the 50 year old generator is exceedingly unlikely to sound just like it did when it was new.

 

As far as crosstalk, as Guido indicated, crosstalk comes from many sources - tonewheels are mounted in pairs, multiple pairs are on the same drive shaft, there are a multitude of little compartments in the generator. Then the wiring - none of these wires are shielded, and they all run in a big bundle of wires, both inside and outside the generator up to the keyswitches. So the amount of crosstalk is yet another variable.

 

When you start taking a Hammond apart, and find that there are bolts holding panels in place every inch or two all the way through, and realize that all of this wiring loom was hand done and hand soldered - you realize that our society of today will never put in the time it took to build such a product. Of course, they were NOT cheap at the time. My aunt bought a CV and 20 watt cabinet in the early 1940's, and paid about $4,000 for it. At that time, many homes in the area were only $5,000 or so.

 

If one had unlimited funds and resources, a modern mechanical tonewheel design COULD be made using lightwaves and photocells instead of metal wheels and magnetic pickups. All wiring could be shielded, and a very pure tone could be developed. However, at the end, it would not have all the imperfections that organists and audiences like to hear in the Hammond sound.

 

[Joe Muscara]

Thanks for the reply, Guido, as well as Craig and MBK.

 

Guido, you say that the amplitude is "important," but now what I wonder is how important. IOW, if I measured my A-100, would this get the Mojo to sound 75% like it, 90%, or something else? Would it be dumb luck if it made Mojo sound exactly like it because you happened to match other factors accidentally?

 

I hope none of this comes across as criticism of VB3 nor your work. I am just curious about how close one can get with this.

[Jim Alfredson]

It is certainly a big factor, Joe. When I did my tonewheel set for the XK3 based on my 1958 B3, the biggest difference I found between the default digital tonewheels and the real '58 B3 was that the XK3 default was even all across the range of the keyboard, whereas the B3's tonewheels had a sort of "smile" curve to them. In other words, the bottom and top tonewheels were louder than the middle. Even that small change made the XK3 sound more "authentic".

 

When it came to crosstalk or leakage, I got as close as I could using the various parameters in the XK3, but often found myself wishing I could vary individual levels of the harmonics per tonewheel, rather than just the overall level and EQ that the XK3 engine offers.

 

For instance, the leakage per tonewheel on my '54 C2 is very different than that of the '58 B3. I'm not sure if that's due to the age of the components, the technician that initially set up the generator, whether they changed where tonewheels were located in the generator over the years, or all of the above. Not being able to individually change the amounts of harmonics per tonewheel makes it very difficult to create a tonewheel set based on my '54 C2 that sounds different from the one based on my '58 on the XK3. But the two organs definitely sound different.

[Craig MacDonald]

When it came to crosstalk or leakage, I got as close as I could using the various parameters in the XK3, but often found myself wishing I could vary individual levels of the harmonics per tonewheel, rather than just the overall level and EQ that the XK3 engine offers.

 

That's an important point to note, since crosstalk/leakage is primarily coming from other tonewheels that are in the same "chamber" or beside the primary tonewheel, it's going to be different depending on what note/tone is being played and what other tones are coming into play based on drawbar settings. I doubt that most clones recreate crosstalk/leakage in this manner. None that I am aware of allow you to tweak parameters to this degree.

 

I recall a recent review of a clone (I think it was keyboard magazine and the SK1) that described the leakage us unrealistic on certain settings, because it simply sounded like someone was laying their arms across the keyboard. That's not how leakage really sounds.

[AnotherScott]

That's an important point to note, since crosstalk/leakage is primarily coming from other tonewheels that are in the same "chamber" or beside the primary tonewheel, it's going to be different depending on what note/tone is being played and what other tones are coming into play based on drawbar settings. I doubt that most clones recreate crosstalk/leakage in this manner. None that I am aware of allow you to tweak parameters to this degree.

 

I recall a recent review of a clone (I think it was keyboard magazine and the SK1) that described the leakage us unrealistic on certain settings, because it simply sounded like someone was laying their arms across the keyboard. That's not how leakage really sounds.

I wonder if VB3's modeling takes this into account...?

[Craig MacDonald]

Yes it would be interesting the hear from Guido as to how he models/creates the crosstalk/leakage. However, that might be proprietary.

 

BTW it's a similar concept as key click... On some clones, I'm pretty sure that the key click is just some noise that is added, and it can be turned up or down.. HOWEVER, in reality keyclick varies based on what notes/tones/drawbars are being played... I recall hearing that the NORD C2D is introducing a new key click scheme that creates the keyclick in this manner, and from what I heard on one of the C2D demos, it sounded much more realistic (although I really haven't heard a particularly good C2D demo yet!!).

[ZioGuido]

VB3 recreates the crosstalk considering a number of factors, first of all the cross-modulation between wheels residing in the same chambers inside the generator, then the wiring from the generator to the keybeds, and then all the wiring made of resistor wires below the keybeds, which is where the greatest part of the crosstalk is generated.

[JMcS]

I recall a recent review of a clone (I think it was keyboard magazine and the SK1) that described the leakage us unrealistic on certain settings, because it simply sounded like someone was laying their arms across the keyboard. That's not how leakage really sounds.

 

Now this is misleading ( ) since it implies that the SK-1 produces this sound. Here is the text from the article:

 

"If B type 1 or 2 is selected, four further tonewheel sets show up one editing level deeper. Real B-3, '80s Clean, Noisy, and Noisy60 - this last one has the most crosstalk and other grunge, and was my favorite because it added real chewiness to the sound without being musically obtrusive. By contrast, some other clones' "leakage" simulations sound like a background sample of someone laying a forearm across the keyboard."

[Craig MacDonald]

JMcS, you're absolutely right and I stand corrected.. however I was correct when I related that it was in a recent clone review, and it was the HAMMOND SK1 review, however it was NOT the SK1 that was being referred to.. Thanks for the correction.. it was not my intention to mislead anyone except to highlight the fact that some clone leakage had been referred to as sounding like an arm across the keys. Sincere thanks for the correction!! And note JMcS that I was not trying to slam the SK1.. there is a lot to like about the organ sound on the SK series.

[Joe Muscara]

VB3 recreates the crosstalk considering a number of factors, first of all the cross-modulation between wheels residing in the same chambers inside the generator, then the wiring from the generator to the keybeds, and then all the wiring made of resistor wires below the keybeds, which is where the greatest part of the crosstalk is generated.

Dude, you rule. Do you ever sleep?

[Jim Alfredson]

The leakage varies note per note with the VASE III engine from Hammond. It is closer to the leakage on my '58 B3 than the '54 C2, though, in terms of what actual harmonics are present on each note and the amplitude of each of those harmonics. My guess is that, like the C/V, it's modeled on a later Hammond B3, which has different filtering caps and perhaps even tonewheels in different places compared to earlier models. If I had the time, I'd compare my '74 B3 to the XK3 but I don't right now. My guess is, however, they'd be the closest.

 

So this really begs the question: Is there one crosstalk model in VB3 or different crosstalk models?

 

It also begs the question: Does it really matter? Are you going to hear such tiny differences on the bandstand or in a mix?

[ZioGuido]

Do you ever sleep?

 

Next week I should have a surgery at my nose, after that I hope to manage to sleep at least 7 hours a night

[Joe Muscara]

Do you ever sleep?

 

Next week I should have a surgery at my nose, after that I hope to manage to sleep at least 7 hours a night

Deviated septum?

[WheelHead]

 

About the custom service of Crumar, they did take care of me. I needed to replace a couple of keys, and I requested them to send those keys. It took a while because the snow storm and the truck drivers' strike. Also, the company was the process of moving. I was a little bit surprised when I received the package, but this proves they do take care of the Mojo users.

 

About support:

 

Remember too while people are wondering if they will get the new emulations for older Nords of the upgraded organ engine used on the C2D, my Hamichord is **over 3 years old** and NEVER had the VB3HE, YET it was upgraded with the VB3-2 that was a MAJOR, MAJOR, MAJOR upgrade. Other companies in the boutique organ business you have to upgrade whole boards that could cost $1500 or more.

 

Thats the beauty of the Windows Embedded system. Major proprietary-board-or DSP ROM flash programming is not necessary that could take a LOT more time and programming. Guido can improve and update this on a whim and not a major project that appears once in a year or two years (updates to sound). You just double click it and it installs in a minutes and can be reversed back easy.

 

As witnessed here, he may like what someone wrote. Make a change in the organ software and boom! it is up for download. You won't be watching alpha-numeric data ticker-taping on an LCD screen updating an OS with a new sound engine/fix hoping you don't brick it once or twice in 1 to 3 years if ever.

 

Now the 'nose factor' concern? . . I don't know . . I would suspect less updating while more sleep is accomplished.

 

W.

 

 

[Al Coda]

'nose factor'

 

Now,- that term sounds ambiguous to me in respect of sleepnessless.

 

 

A.C.

[Stephen Fortner]

Hey all,

 

I'm working on our next clonewheel roundup, which is slated for the August issue but may move later based on gear availability.

 

A bit of good news I just got is that Andrea and Guido are sending me a Mojo for review--actually it's slated to be Tony Monaco's.

 

So here's my druthers list for what goes in:

 

- Mojo

- Nord C2D

- Hammond SK2 (have the SK1 in hand but not the 2 yet)

- Studiologic Numa Organ

- Hammond XK-3C Pro System (lower manual, pedals, stand, etc., as a familiar reference)

- DLQ KeyB Duo

 

Hmmm, except for the Studiologic, there's a bit of a dual-manual theme going here.

 

Also working on software list. But for hardware, any other must-includes?

 

And yes, when I get all this stuff set up in one place, we should do a SF Bay area forum hang / clonewheel playing session.

[Tobias Åslund]

How about the Hamichord M-C3 with Exp edition?

[kanker.]

Maybe the Electro 4D if it's out in time as a comparison to the C2D? Kurz KB3? Kronos? Not sure if any are must includes, but food for thought.

[Gary75]

There'll be a review coming soon....

 

Found a brief review here though

 

http://www.norduserforum.com/nord-c1-c2-c2d-organ-forum-f13/nord-c2d-press-release-and-pics-t2140-70.html

[LX88]

That is going to be a heck of a shootout.

 

It is interesting that Tony Monaco is getting a Mojo. I wonder if he is an endorsee or if he bought one.

 

 

[AnotherScott]

Kurz KB3? Kronos?

I like the idea of perhaps a companion piece, covering those that aren't full clonewheels in ergonomics, but still lay claim to clonewheel emulation. Kurzweil KB3 in a PC3K, Kronos 61's CX3, and Roland Jupiter 80 come to mind (in the case of the K&K, choosing the models with the most organ-suitable action). Perhaps you could hook up an Ocean Beach Drawbars unit to them to try to get more of the operational feel. The dedicated clonewheels are obviously going to offer the best overall experience, but for those organ aficionados who can't afford to dedicate a whole board to their organ sound, it would be nice to get some thoughts about just how close they can get with a multi-function board if that's what they feel they need to go with, while focusing on keeping the organ capabilities as a priority.