Moog modular switches

[Trigger]

Hello all:

I'm on the hunt for some NOS Switchcraft lighted lever switches, part #25201L. These are the clear, 2-position pre-colored slider switches that go into the earlier 993 and CP3 modules.
I've checked with Switchcraft, Mouser, Digi-Key, et.al., and was able to find a couple of non-locking replacements--but I obviously need the locking variety (hence the "L" suffix).
If anyone has a source or can steer me in a promising direction, I'd really appreciate it. Here's a reference sheet...

Thanks!!

[BrianK]

Hey Trigger - I know those switches, quite beautiful. The later ColorGlo slider switches from the '70s are much more common, but these are really exceptional-looking. May I ask why you need them? Are you restoring a synth or building something.

Sad to say, these are among the hardest parts to find on a vintage Moog. I know a few people who found them (or similar) in vintage surplus houses, but you've probably already been looking?

[Trigger]

Hi Brian:

I'm in the process of acquiring the more hard-to-come-by parts before I begin my system restoration. So far my existing switches have been fine, but I'm stockpiling for the time when they really will be extinct. Most everything else is available, but these switches have been a challenge. They were only used for a year or two before Moog went to the blue/red-green/white lighted sliders. Interesting that Gene Stopp and others have mentioned that those sliders were one of the most difficult parts to source for the Emerson Moog project. When Moog makes parts and modules available again (hint, hint) , maybe this won't be as much of a problem.

There's an interesting phenomenon I've found so far--maybe one of the reasons that the 901Bs have a different sound than the 921Bs. It's a little spike on the top of the saw waveform. I'll see if I can upload a scope pic soon. Maybe this has been mentioned before here or on other forums. Perhaps Terry has had experience with this and can weigh in.

Now for my next search: anyone know where I can find ribbon controller ribbon for my 956??

[CZ Rider]

Just for fun I took some scope shots of the 901 waveforms. These 1969 revision 901's do not look like those I see posted at various sites. Sines on all oscillators just have a small upward dimple where the two ends meet. Many I see have this larger dimple that goes downward. Guess it all depends on how you calibrate them. I did all my own calibrations and adjustments.
One of the unique characteristics I notice in the 901's is phase cancellation between two 901's is less pronounced than it is on many other type oscillators. I can mix two or three of the same amplitude sawtooth in unison, and get minimal cancellations. Most oscillators with that same patch have a much deeper cancellation, almost as if someone was rasing and lowering the volume. The bass register on two 901's phasing remains a more constant energy level too. They still phase and make cancellations, just not as deep as other oscillators do. I even tried other oscillators thriough the CP-3 mixers to see if that is a contributing factor, but with other type oscillators the cancellations are just as deep. One of those strange properties the 901's have.

Here ars scope shots of one of my 901's:


While I had the scope/camera set up, I took some of the Minimoog. I have individual outs, so I can get pre filter/VCA shots of the Mini oscillators. This one is a second generation 1974 oscillator board with the 3046 IC's. The tri, tri/saw, and saw were all set to the same settings as the 901 shots. The Mini oscillators are a little hotter, but still very low energy compared to typical 10vPP oscillators. The square/pulse shots are 1/2 the setting to get the whole waveform in.


Interesting to note, all the Mini square/pulse waves are negative offset from a zero base. Perhaps done for modulation purposes as the Mini modulation mixer inverts this and amplifies by a factor of two. (Easy to get a square wave trill with an interval that keeps the base note). I tried to patch Mini oscillators through my CP-3 and Moog modular and noticed the Mini oscillators distorted easily. Did not realize it was this negative offset in the square/pulse waves that was causing this. It easily hit the -6V wall when mixing a few waveforms/oscillators together. Had there been no offset or a positive one, the mini oscillators would have mixed in easier. I was wanting to try the early Carlos method of adding a Mini oscillator bank and it did not work as I had expected because of the offset. Will need to build a cirucit to get them back where they will blend in with the other modular levels.

EDIT: Both 901 and Mini oscillators playing an A 2 octaves above 440Hz, so 1760Hz. The waveforms do distort more when getting into that super high range.

I did recently post a YouTube video showing the 901's range and had a scope in the video to see what was going on. That scope is getting it's input from the negative CP-3 output. I do have two CP-3's cascaded together, with the two positive outputs of the one CP-3 feeding onto a second CP-3 to get controlled clipping. I prefer the clipping just a bit on the negative side. I turn it up at the end and can see the flat lines top and bottom on the scope. (really distorted) I do seem to be able to get more than six octaves from these, and the octave switches are tuned quite well. These are 1969 revision 901's with the CA3019 diode arrays. And you can see/hear the minimal phase cancellations, especially at those low notes.
Video here:
R.A.Moog 901 oscillator tuning range demo

[MC]

901s have a beefier output stage which are designed to allow them to be used as modulators. The minimoog VCOs don't have a beefy output because they were hardwired not patchable modules.

[Trigger]

Here's that 901 waveform pic as promised:

Check out that little overlap at the top of the wave. Sure looks similar to your pics, CZ...
Thoughts?

[MC]

Here's that 901 waveform pic as promised:

Check out that little overlap at the top of the wave. Sure looks similar to your pics, CZ...
Thoughts?

That little overlap is a consequence of the UJT in the circuit. Google for the AES paper that Bob presented, he discusses the 901 circuit and this anomaly.

[museslave]

Damn, I'm going to have to look back at video, but I don't think my oscilloscope experience of the Minimoog had my square waves in the negative.

But yes, in Bob's desktop notebooks, he speaks quite a bit about that notch in the triangle.

[thealien666]

... I don't think my oscilloscope experience of the Minimoog had my square waves in the negative.

Nop. Same here, the square wave has no negative offset on my Minimoog either (as seen in the pic below). My scopemeter was connected directly on the "high" line output of the Mini though.
The negative offset is probably removed in the VCA circuit later on. CZ Rider was connected directly on the oscillator board (or equivalent outputs)

[CZ Rider]

Dave Brown has a nice page with some interesting scope shots of the 901. Dave noticed the waveforms distort more the faster the oscillation.
Dave Brown's 901 page

The waveforms on my 901 were taken at two octaves above A-440. Very little distortions at that frequency, but a few octaves higher and the waveforms begin to distort. Dave also got nice waveforme at low frequencies.

Those Mini oscillator square/pulse waves are indeed negative offset. The Modulation mixer/amp for osc. 3 inverts this to a positive offset. No doubt when using the square/pulse waves as modulation source these are positive going only and not bipolar. This practice is common, and both the Roland 100M and Aries oscillators here have positive going square waves, while all other waveforms are bipolar. Something to be aware of using a DC mixer, adding in a voltage to offset may be needed to keep those type square waves from clipping when added together. This was the case with the Moog CP-3 DC mixer where a few the negative going squares clipped in a negative direction easily. The Mini filter is responsable for making the square after the filter look bipolar again. The Roland and Aries filters do the same, as will the Mini external input. Mini waveforms get quite distorted from the original ones generated if you look at them after the filter and VCA's, even with the filter wide open.
The only reason I mentioned the Mini waveforms is I am working on a project with a Mini oscillator board and noise/modmix/regulator board to possibly use as a Moog modular expander. That offset is something I plan to tackle by adding an inverter with an offset to make each of the three oscillator squares bipolar again. A few other things to add too, like sine shapers after the triangle waves. Have some Moogish looking front panels for the oscillators, and will make more panels for the mod mixer and noise outs white/pink/red. And a few other utilities like Moog accessory ports.


Might have to clone a Moog portable case to house the +10/-10 volt modules.

[BrianK]

Hi Brian:
Most everything else is available, but these switches have been a challenge. They were only used for a year or two before Moog went to the blue/red-green/white lighted sliders. Interesting that Gene Stopp and others have mentioned that those sliders were one of the most difficult parts to source for the Emerson Moog project.

Yes, it is these odd low-production parts that are a limiting factor. We were lucky to find the later slider switches in a medium quantity. The toggle switches you want are Switchcraft LeverLite, but you probably knew that...

I am told (maybe true) the first set went onto Mick Jagger's Moog as seen in "Performance," which would be Sept 1968. (This is also supposedly the synth that went later to Tangerine Dream and then to Hans Zimmer.) It does seem that by 1970 they were using the sliding ColorGlo switches; which were probably cheaper. So maybe used for a year to maybe a year and a half? I do think they are the coolest of all the options, but (luckily) the Emerson rig uses the more common (slightly) sliding ones.

[Trigger]

I am told (maybe true) the first set went onto Mick Jagger's Moog as seen in "Performance," which would be Sept 1968. (This is also supposedly the synth that went later to Tangerine Dream and then to Hans Zimmer.) It does seem that by 1970 they were using the sliding ColorGlo switches; which were probably cheaper. So maybe used for a year to maybe a year and a half? I do think they are the coolest of all the options, but (luckily) the Emerson rig uses the more common (slightly) sliding ones.

Here's my 993:

It has a date of 3/68; that would seem to predate the Stones/Franke system. Its serial is #1001, which would make it the first production model?
I believe CZ Rider's Ip is '69, and I think his system has ColorGlo switches. Maybe they were more cost-effective than the Lever-Lites. If so, the Lever-Lite models would be few and far between.

And Performance is great--during the Moog scene (and Mick with the fluorescent tubes), sharp eyes can pick out a Mello MKII in the room I think it's currently on display at the Rock and Roll Hall of Fame.

[BrianK]

#1001 is likely a first one, but hard to say - many are unnumbered, and sometimes there are "lab" versions... as you say; production is different. These are indeed beautiful, and do yours have 3 positions? Several of these older Moogs have 3-position switches, but use only 2 settings are used (center/down and up). The color change only happens on the upper setting, to visually indicate this. In these cases, it may be another reason why an expensive switch (3 positions used for 2) was substituted with a cheaper 2-position model. (And the 1970 era when these changed was the dark period for Moog financially, just before the sale to Waytena).

The Stones Mellotron may or may not be the same one - Brian Jones had one for certain, but was there another? I know one in England that claims this as well...

[CZ Rider]

The sliders used on all 1969 and later Moogs were UID brand "Ultra-glow". They all had cool names back then for their products. Not cheaper, but perhaps less expensive than the Switchcraft "Lever-lite".

Even though those Switchcraft type are beefier, it could have been an EOL or reliability issue for the change over. But it looks like they only used them around 1968.
The use of these switches directly correlates with the introduction of the CP-3 mixers and the grouping of three oscillators per one driver forming a bank. The Dolenz system from September 15, 1967 shows the use of unlighted toggles with no standard etched CP modules yet. And has the grouping of one 901A driver for eight 901b oscillators. This practice changed with the introduction of the 1968 models I, II, and III. Other than the use of lighted switches and CP-3 there may have been other improvements. Unknown when the 901's began using the CA3019 revision, but that 9/15/67 system, still had the older top hat diodes and all pots were those "hubcap" type (Mallory?). Sometime, perhaps starting with the 1968 models, Moog moved over to those AB type J pots, lighted switches and standardized CP panels with the three oscillator bank grouping.

The earliest system I can find with those Lever-lite switches is the Mort Garson one sold March 4,1968. (And now Triggers system 3/68.)

And the earliest system with the UID Ultra-glow I can find would be the Temple University system in Philly. That one was sold on December 13,1968 and had the UID type.
Old vintage photo of the Temple Moog.

So it looks like Moog made the change over to UID switches by the end of 1968, and just about every 1968 dated system I have photos of has those cool looking Lever-lite switches. The Beatles Moog system sold in January 15,1969 can be seen with the UID type switches.

I have read much misinformation about the Rolling Stones system. One site claimed it was the second Moog made. Perhaps the second one imported to the UK, or the second use in a rock tune. But those fan sites have to be taken lightly. I did notice in the film, the Jagger scene with the Moog, it is not powered up. (The Lever-lites aren't lit.)

Moog probably still had a few of those Lever-lite's around for spares. And I have seen one or two used in various custom Moog modules after 1968. The custom 700 percussion clock unit had two of them.
But my best guess is Lever-lite's used in modular systems was a 1968 thing.

[EricK]

CZ,
Of all of the Moog research you have done and posted, what can you tell us about those florescent bulb controllers? I can only assume that perhaps those were the prototypes for the Buchla Lightning wands?

Does anyone have any schematics?