Moog Modular Keyboard inquiry

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1

(no modular forum yet?)

Well here goes. Can somebody outline for me, the various keyboards that Moog made over the years to accompany their Modular synths.

I’m aware of the 5 octave walnut model, one that offered a split (I think), one that offered realtime (or full time) duophony, and a 4 octave variant in Tolex that was made to accompany the Model 15 in Tolex (in the Model 15 documentation you an see it sitting on top of the keyboard cover/case).

All appear to have the large DIN/BUS connector for connections to the back of the modular, brought fwd to the CP row or normalled to other modules.

There is not a terrific amount written about these, certainly the few that come up for sale on eBay are usually broken and fetching $3K (about to change when Moog releases theirs, I’m sure).

Thanks.

2

Well, AFAIK there have been only two basic technologies / keyboard interfaces for Moog Modulars. First the standard monophonic variant and the second the duophonic version.
The monophonic version provided one control voltage and one STrigger event, the duophonic version two of them. That’s all.
If you want to connect a keyboard like this to a Moog Modular you just need 5 or 7 cables:

1.) +12V provided by the main cabinet
2.) Ground provided by the main cabinet
3.) -6V provided by the main cabinet
4.) Pitch control voltage provided by the keyboard
5.) STrigger event provided by the keyboard
6.) 2.nd pitch control voltage provided by the keyboard (duophonic version only)
7.) 2.nd STrigger event provided by the keyboard (duophonic version only)

The technology behind it is rather simple. The 950 keyboard interface is quite a primitive. A resistor chain working as voltage divider row to provide the control voltage and a simple transistor inverter working as current sink for the STrigger function, so a broken 950 interface should be replaced easily. A price of 3k is ridiculous.

More information about the 950 on my clone page http://www.analog-monster.de/mmt950_en.html

3

Thanks for that.

I must have seen a modular controller offered by another company that had a split and mistook that for the Moog. Looking around just now, I see that it’s the original synthesizers.com keyboard offered a hard split point by octave. Roger Arrick no longer offers this model. There were some complaints about the quality and feel but I think the design (bar vertically mounted jacks) was sound.

Moog’s vintage keyboards are puzzling to me. There is a good description (which appears to be based on the original doc) here: http://www.moogarchives.com/m951.htm

Looking at the 951 description, there appears to be Minimoog-like (lowest note priority) scheme but the 952 description goes on to suggest that the second note is only considered when a ‘high’ note is played. I am basing this assumption on the fact that it mentions high note at all. And some have a glide on/off switch while at least one pic I saw had something to do with ‘HOLD / NO HOLD’ and I wasn’t sure if this was simply to force a gate on (trigger that never closes like the switch on the front panel of a Voyager) or something else.

It is therefore possible that on a real 952, any single note played will be considered the low note and a 2nd note played which is higher than the first note becomes the 2nd note but a 2nd note played below the first note steals from the first note? And what happens if you pay legato with one voice attached to the Duophony keyboard?

I have an extensive understanding of note/voice stealing and distribution algorithms (the Kurzweil 250 was an early king at this), round robin, fixed voice (no stealing), start from low (Oberheim x voice) and the modes of the Mutable MidiPal not to mention the HexInverter alternate firmware and all of the work that Dmitry (Muffs user ‘rpocc’) has been working on.

I’m looking for something that will give me a hard split point -or- a really really well engineered and flexible note distribution algorithm. The ‘dream’ of a fully polyphonic Modular (playing the same note across x voices) is a bit far fetched to me; two of the same notes is mildly interesting but also unnecessary. Anything else is of interest if well executed.

The Model 15 has me thinking about all of this. If you had 2 voices which were identical in form, you could play the 952 keyboard to your hearts content and not worry about any of this. But if you’ve got one voice composed of the 921abb with a traditional Low pass modulated by a single 911 but with a gated VCA, and a 2nd voice produced by the 921 through the FFB gated by the other VCA, trying to play anything useful (not experimental :smiley: ) anything but a hard split is going to be difficult/unpredictable. There is a video or two of somebody playing two Voyagers Duophonicly and it’s shameful : )

I assume Moog is thinking about all of this right now as they work out final specs for the 962 (I think it was called?), now “Duophonic” keyboard. There may be an original Model 55 owner that wants a 952 exactly but I think the most important thing is that the keyboard attaches properly that it’s solid/stable and of proper build quality, and if possible that they incorporate some modern features and flexibility without over engineering something that will need firmware updates for the 6 months following release. Purists are also going to want to retain the vintage aesthetic.

The original 952 had two sets of controls, one per channel; the new Duophonic, at least the early pics of it, appear to only show a single set; similar to the 951.

I really just want a way to split. I do this now with my Synth.com keyboard, a pair of Midi->CV converters and two voices which are not similar at all. Sometimes I squeeze Minitaur into the mix and play that on the lowest two octaves with two Oberheim SEMs on the upper register… but it’s all about being able to isolate. Interested in hearing other ideas if anybody has anything to share in this regard.

4

I have three of the original Moog keyboards with an old original 950, a newer standard 950 and a Norlin era 952. While those controllers are nice, I mostly use an 88 key weighted Roland MKB-1000 as the main controller. One of the many dissadvantages of using the original type analog circuits is drift. The analog type uses a charged cap to hold the last note played, and it will eventually discharge. So if using an analog keyboard to transpose a sequence or playing a drone, over time it may drift enough that is goes out of tune.
A digital scanned keyboard will hold indefinitely and if equipped with MIDI can layer or split depending on the model. The Roland I use is great for this as it has assignable split where I can put the modular on the lower three octaves while using the upper half for a different synthesizer or patch from a programable module. The possibilities are endless and something like this would be a dream back in the late 60’s early 70’s. You would have needed someone to make a custom controller to layer in another voice to play along with the modular. With MIDI this is easy to do. Right now I have the modular split on the bottom octaves with the Minimoog playing polyphonically on the top portion. Using a Kenton Pro Solo on the modular on channel 3 and an MOTM-650 on channel 16 to play the Minimoog polyphonicly patching in the three oscillators.
As nice as those original controllers are, it’s tough to go back when you can layer and split all kinds of voices from one high quality keyboard.
Here are the originals I have here, a 1969 950 on left, an early 1967 950 in the middle, and a 1974 952 on the right.

The main differences are the electronic circuits on the various models.
The original 950 had a simple interface with a large/long type Pratt-Read action with three J wires. These were the original keyboard controllers and some of the early ones had crude envelope generators with no release times on the right side. Depended on what you needed, as back then most were custom ordered.
Early 950 control panel:

The next generation standard 950 featured a switch that could either be used with the scale programer or polyphonic oscillator bank. Had a shorter throw Pratt-Read with bell crank action similar to what was used on the Minimoog
Standard 950 control panel:

The back had an extra two multi pin connectors for attaching the scale programer or polyphonic oscillator bank.

Moog would later release a less expensive version 951 that was mostly the same as the 950 without all the extra connections for the scale programer and polyphonic bank. The 951 was a few bucks less than the 950.

The last Norlin era keyboard was the 952 two voice keyboard. The second triggered vioce could be patched to anything and was activated by holding a second note. Hi/low priority as this is analog and no digital key scanning was done back in 1974. The keyboard was a single J wire type Pratt-Read.
The control section of the 952.

The 952 pairs up nice with the 1150 ribbon controller and would be my choice for the most versatile vintage Moog controllers.

Moog would make any custom controller you wanted if you had the money. So it is not uncommon to see variants of the three different keyboard circuits. But they were ususlly one-offs and unique.
Here is a pic of Bob playing the original Moog two and one-half octave keyboard in front of the custom 700 series system at MOMA back in 1969.

5

Great stuff CZ, thanks for that.

So the 952 duo phonic… what would happen if you played legato style? Sounds as if the 2nd note would engage vs the first note changing pitch but not firing the env gen. Not ideal is it?

Like those funky Centronics printer interfaces. I think I had the same thing on my Epson MX-80 back in … ummm, the early 80s. (I still have a ream of dot matrix tractor feed paper in my garage! Right next to my Commodore Pet [mouse house])

Completely understand about the capacitor drain issue you mention (especially on an aged keyboard). I suppose if you simply ‘played’ and didn’t use it as a voltage source to transpose (your example), then each key pressed or held for a reasonable period, would work well enough.

Now a question for you… knowing what you know about these keyboards and about Moog’s announcement (of something called a 962 or generically a Duophonic kbd) what would you expect they are about to release? Any thoughts on tradeoffs, etc. (I suppose this is more of a marketing question than anything that speaks to capabilities because, of course, they are capable of just about anything considering what is done with micro controllers these days).

6

Tough to say or guess, but I would imagine it would be a digital scanned keyboard and not an analog type resistor string. (Fatar board versus the old Pratt-Read too.) All of the old Moog keyboards used a resistor string that not only relies on a charged cap to hold the voltage, but also a good contact for a clean voltage for pitch and trigger. (No pitch shift or trigger bounce.)
While a digital method in an analog system usually had some type tradeoff, a keyboard like those used in old modular Moogs is really just a switch. Digital does on/off type switching very well since it is based on switching zeros and ones. So digital is an almost perfect solution for handling the keyboard triggering, CV hold, and gating/routing for mulit voice. The portamento should be the analog part of the circuit after the digital derrived pitch CV.
Even when new, there were mods for the Minimoog when using pitch to CV devices to disconnect the keyboard analog hold circuit for pitch stability. Has more to do with the method than aging components as the Minimoog would always slowly drift as the cap discharged. The digital method eliminates that issue. So I would imagine today that would be the way to go?
I think the new keyboard photo is just a mock up and would most likely have more controls on the panel.

7

CZ

Is there any more info regarding the basic envelope generators featured on the early 950’s ? I’ve heard this mentioned before.

8

Not much official info on those. I have gathered some info from photos and interviews.
Here is an early 950 with the extra envelopes on the right side.

Some time ago there was an Ebay auction for the electronics from an old 950. Here are a few pics from that auction.
Front panel:

Strange looking controls. Looks to have two seperate envelopes, each with a switch to select fast/slow attack times. An attack time, (perhaps, can’t make out the label?) with a decay time and sustain level. Do not see a release time? Might be like the Minimoog envelopes, or like an organ with no release.

And a pic of the back showing the small dual circuit:

Would be a fun circuit to clone if I had the schematics. Could always use a different Moog envelope generator.

This is all from the early days of the Moog modular, probably pre 1967 or so.
Here is an interesting quote from a Polyphony interview of Bob Moog talking about the early days and how some of these designs came about:

9

Excellent archaeology work CZ…these EG’s are indeed highly desirable and as you say if only the schematics were available. ( perhaps somewhere?)

I notice that these units correspond to the Carlos “Touch Sensitive” custom modules on her modular.
It would be very interesting if this could be confirmed as these modules are still an enigma.
But the link with the keyboard is a tantalising clue.
As one of her keyboards incorporated pressure sensitive capacitors it seems logical they would adapt this EG unit to produce the pianist " Percussion" (attack) Decay and Sustain.

Let’s hope one day the schematics turn up.