MATRIXSYNTH: Minimoog Change List - Minimoog Versions

Sunday, February 17, 2008

Minimoog Change List - Minimoog Versions

via Brian Kehew of The MOOG Cookbook:

"Minimoog MODEL "D" Changes:

At first look, all Minimoogs seem alike. It seems that the Minimoog is something unchanging that we all know and recognize. They are similar to each other, but there are many features that changed over time. You may already be aware of a few differences, but most people will be surprised at how many variations there really are.

One of my main goals for this site was this very page: to show the developments in the main Minimoog design (MODEL D), and give an idea when the changes happened. To my knowledge, this type of listing has not been done for the Minimoog. Once you see it - you should be able to tell what is "original" on a Minimoog. In some cases, you will even be able to guess a Minimoog's serial number quite closely after only a quick glance! Like "trainspotting" (identifying nearly identical trains by small distinguishing features) this is trivial, but fun.
The process was simple - I compiled a database of over 100 Minimoogs. By asking owners detailed questions, I was able to determine the commmon developments. Cross-referencing this data to known dates of production, it becomes easier to see WHEN things might have happened. Note: This is by no means foolproof, and there are individual Mini's that do not fit the pattern. For now, we will assume that they are mutants/modifieds, and simply note the main trends.
The Changes:
Read through these links first, so you will be familiar with the details. Then, I have arranged a timeline of the changes below for clarity. In the future, I will have photos of the changes, a helpful visual reference...

* The Badge
* The Factories
* The Front Panel
* Graphics
* Wheels
* Left-Hand Switches
* Panel Switches
* Oscillators
* Octave Buffer Board
* Rear Cover
* Power Cable
* Pointer Knobs
* The Wood Case

* The Questions used to make the database.
* TIMELINE of Changes


(This is the "logo plate" above the keyboard that identifies the company)

* R. A. Moog: When the company began making synths (1964/65), this was the name, carried over from Bob's Theremin business. This metal nameplate is only found on the earliest Minimoogs from (late) 1970 through 1971.
* Moog/Musonics: After Waytena bought the R.A.Moog company, it was merged with Musonics (his own company) and the Minimoogs from this brief period (1971) bear this name. A metal plaque.
* Moog Music Inc. After Moog was sold to Norlin/CBS in 1972, this became the name that would remain until the last Minimoogs were made. MOST Minimoogs have this plate, a vinyl material.


(Moog had several plants during Minimoog production, relatively close to each other in upstate New York)

* Trumansburg: The original factory, built Minimoogs from late 1970 through 1971.
* Williamsville: after the Musonics purchase, operated from March 1971 to 1977.
* Buffalo: a much larger plant, made Minimoogs from 1977 to 1981


(Construction of the front panel behind the knobs)

* Metal - A thin sheet of smooth aluminum.
* Metal with Plastic - same as above, but with a thin clear sheet of plastic to cover/protect it.
* Plastic - a heavier vinyl/plastic panel, with a textured surface.


(This is the silkscreened labelling on the front panel)

* "VOL." - the earliest Minimoogs (metal and metal/plastic panel) have different designs. The time settings are marked in seconds, the Osc.2 & 3 fine tune knobs have cents/100 divisions, and the Volume knobs say "VOL."
* "Volume" - the design used on all vinyl panel Minimoogs: the knobs say "VOLUME", the times are in divisions from 1 to 10, and the Osc. 2 & 3 tunings knobs are incremented from +/-1 to +/-7.


(On the left-hand modulation section, the wheels and switches underwent a few developments)

* Clear Wheels: the earliest design, a beautiful look.
* Solid White Wheels: same shape as before, but in an opaque white plastic.
* Serrated White Wheels: These have ridged, wavy edges for better gripping.

# Clear Lighted Wheels: same shape as early clear wheels, but with internal lights to show them off. Only on the last series of 25 "presentation" Minimoogs.


* Decay/Glide switches are Red Momentary pushbuttons on the earliest R.A.Moog Mini's. This may be to make the instrument more "performance oriented" as the sound can "change" easier with momentary switches.
* White Mini-toggle switches. Some early R.A.Moog instruments have small toggle switches (NOT momentary) for Decay and Glide. On some, this appears to be a retrofit, as it would be more usable than the buttons. On most, this looks like the original factory issue design.
* White Rocker switches; the standard white plastic rocker switches found on almost all Mini's. Begins during the R.A.Moog period and remains until the last.


(These are the colored rocker switches used all across the front control panel for modulation, the mixer, etc.)

* Blue and Orange - the most common color scheme - almost all Minimoogs have this setup. In case you never noticed, Blue is for audio routing, Orange is for modulation routing.
* All White - very few Mini's have this, but there are a few known examples, mostly early Mini's. It looks quite good, actually.
* All Black switches - again, another variation that seems to be original. The factory had them around, as the Power Switch is usually Black. This also looks very cool!
* All Blue - there are rumoured Mini's with all-blue switches (makes sense - it would have been EASY to do at the factory). At least one prototype had this.


(This is an important and controversial point for some Minimoog owners. The Oscillators were changed, at least a few times, in order to make the Minimoog more reliable)

* R.A.Moog - these are the Oscillator circuit boards for the earliest Minimoogs. There may be only about 100 made with these boards - they have "RAMOOG" written on the circuit board itself. The do sound different than the later oscillators, but are relatively harder to keep in tune.
* "Old Oscillators" - a term that is somewhat misleading now that we know about the RAMoog boards! However, most people consider these to be the first half of Minimoog production, almost 6,000 of them made, so they are often called "older oscillators". They are relatively stable, except when switching Octave settings.
On the back panel, one can see a set of 7 small calibration holes behind the Oscillators. This is true for most RAMoog and "Older" Oscillators.
* "New Oscillators" - these were specifically designed to keep the Minimoog in tune, a big complaint for the many performers using the older oscillators. The new oscillators have 17 trim holes on the back panel. They allow for especially precise calibration on the high frequencies, and have the Octave Buffer (see below). Moog began these with #10175 to the end, but many earlier ones have had these retrofitted.


Apparently, not many people know about this. The Octave Buffer Board is a FACTORY modification to correct a design flaw in the original Minimoog: When Oscillators were switched between octaves, they would often go out of tune. This small board was added inside the Minimoog just under the top edge (behind the Oscillator section, and mounted to the metal with two small black screws)

Beginning with serial number #5000, this was done on ALL Minimoogs from the factory. I have seen MANY of the earlier units (before #5000), already retrofitted by the factory or factory-authorized service centers. When the Minimoog was sent in for calibration, new oscillators, repair, etc., it would have been added as a matter of course. It's a very GOOD modification to have done and will not affect the value of your instrument. It will, in fact, increase the value, as your Mini will definitely be better with it. (It is possible that the early RAMoog oscillators do not need this modification - we're looking into it)


(This is the removable aluminum cover on the back of the Minimoog)

* Bent - on the R.A.Moog Minimoogs, the aluminum is a flat panel bent into a box shape. It has an open seam where the sides join.
* Welded - on all later Minimoogs, this cover was welded at the seams, to prevent dirt from entering the electronics section (a good idea!)


(The power cable changed several times during production)

* The R.A.Moog Minimoogs have power cables that enter to the Left of the Accessory jacks (when looking from behind). 2 prongs (no ground) and usually brown.
* When the Minimoog was made with the new "Moog/Musonics" badge, the power cable moves to the Right of the accessory jacks. It was originally brown, 2 prong. This is also true for early "Moog Music" Minimoogs.
* Later, it became 3 prong, in black or gray.


(An interesting (but rarely noticed) change in the Minimoogs)

* Most Minimoogs have standard pointer knobs - where one end is pointed and the other end is wide.
* There is a specific period in 1974 where Minimoogs have different pointer knobs, where both ends are the same shape. This may be due to a shortage at the factory, or to keep down costs (Note: these same pointer knobs are found later on the Micromoog and Multimoog). However, they ARE original from this period - many people will assume they have been changed.


(An obvious difference, very visible. I'm no expert on woods so I'm going to look into this with an expert. There are a LOT of different styles, some just variations on wood stain or color. Here are the basics)

* Early Minimoogs have dark brown walnut casings, rumoured to have been cut from trees on Bob Moog's property. They are not stained or laquered.
* The next series of Minimoogs seem to have a dark Mahogany wood, also unstained.
* Later, the Minimoog came in a "butterscotch" colored stain, over an light-colored unnamed wood.These will be slightly glossy.
* Finally, the Minimoog came in a wood with very dark brown stain, almost as thick as paint. It's not as natural-looking as earlier Minimoogs, but ALL Minimoogs are beautiful!

These are the questions that were asked of Minimoog owners. These are basic changes (mostly external) that help us identify any Minimoog. (I will get into more detail about the internal changes at a later date)

* Serial number ?
* Front plate - RAMoog, Musonics, or Moog Music?
* Casing - unfinished walnut, light maple (butterscotch), or dark stain mahogany?
* Front panel - metal, metal w/ clear plastic coat, smooth plastic, rough plastic?
* Factory - Trumansburg, Williamsville, Buffalo?
* Wheels - clear, smooth white, serrated (rippled) white, lighted clear?
* Panel engraving - "VOL" or "VOLUME"?
* Decay/Glide switches - momentary red buttons, white rocker, (other)?
* Panel switches - orange/blue, all black, or all white?
* On the top edge (behind the wood, just above the Oscillator knobs) are there two small (black) screws?
* Number of calibration holes in back panel? (total)
* Power cable (looking from the REAR) - right or left of Accessory jacks? - brown, grey, or black? - 2 or 3 prong?
* IF there are paper assembly tags inside - what is the date?"


  1. The longest-ever post! And not only that, but it has girth as well. A deep topic covering a breadth of issues. OK, not really, more like total timewasting silliness. Which rules, of course.

  2. My minimoog is from Feb 1972.. it has a metal Minimoog, Moog Music badge.. this isn't noted in the list. I figure it is a transition mini between the Moog/Musonics and Plastic Panel Moog Music models. It has: walnut chassis, bent back, metal panel and clear wheels. all boards say RA moog.

  3. Interesting... I'd always heard that there were three versions of the oscillator board, not counting the R.A. Moog board (which I didn't know existed until I read this post). I don't recall all the details (will do an AH archives search later), but one of the three versions used the uA726 heated matched pair transistor in the expo converter.

  4. The last (later) version uses the 726s

    I've seen all 3, the RA Moog ones are easy to notice due to the heatsinking of the transistors.. I actually got a Late verion Mini in for repair which had the very early RA Moog Osc Brd.

    I guess Brian didnt see this page which also outlines minor production changes in minis:

  5. I found this page with a rundown of Mini production changes, some of which differs from what has been presented here:

    There's also an extensive registry of Mini owners, by serial number.

  6. rick beat me to it, sorry!

  7. BTW, to make the history complete, the Welsh Minis should be added to the list.

  8. Thank you Kevin for this great information.
    There was no place before where all the different details were listed.

    keep on turning these knobs

    Till "Qwave" Kopper

  9. That other one is a good list - mine is over ten years old - I just never did anything with it. This list is for external changes only - so you can spot what age a Mini is by the quick visual differences. There are HUNDREDS of internal changes if you start tracking those (which I did, but stopped because there are too many).

  10. Don't forget the Donimoog!

    Ours sounds fantastic, though it didn't beat out the actual Mini in a blind taste test at the studio a few years ago. Also, the orange flip switches just aren't quite the right hue...

  11. Donimoog isn't a Minimoog and shouldn't be considered.

  12. another variation is the physical cabinet construction. Minis before s/n 5000 had narrower sidepieces than later Minis.

    mine is 4192, it has the narrow sidepieces, white smooth wheels, actual time increments on the envelope knobs, the word "Volume" is spelled out, and it has the "oh crap we have to wait for the suppliers 6-week lead time but we need to ship units right now" double-pointer switch knobs.

    it does not have the "buffer board", which is something i need to read about. it just seems like my Mini needs to have the voltage divider resistors in the octave section switched out with .1 percent resistors, as the funky tuning between octaves is consistent.

  13. A thought occurred to me about the knobs. Bob was quoted in Vintage Keyboards as saying that when Waytena was getting ready to sell Moog Music to Norlin, he had them make up several hundred Minis, which were then stacked up as if they were being prepared to be shipped to customers. The idea was to convince the Norlin people that Moog was doing a land-office business. (And apparently it worked.) Anyway, I wonder if this is the period that accounts for the different knobs? If they were assembling a bunch of units in a hurry, perhaps they used these knobs because that was what they had in inventory.

  14. Footnote on the clear wheels, late production, Kevin Lightner began to make clear, including clear with mulicolour led lighting, so a clear does not always mean last 25 missing a badge.
    Footnote on knurled wheels, bought mine with white plexi wheels in 1975 new. That is teh year the micromoog was introduced and it had the knurled wheels so I'd expect around 8900 or so the knurled wheels became standard. In a cross-over I have seen one or two Mini's with the micromoog touchstrip and knurled wheel as more of a custom shop thing.



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