Moog 950B Scale Programmer (1969)
Sixty knobs that let a Moog keyboard play in tune with nobody's tuning but your own.
Overview
The 950B Scale Programmer is one of those Moog modules that barely exists in the historical record — a rack of sixty independent manual controls, each one varying the magnitude of an interval between two successive voltage levels on a 950 Keyboard Controller. That is the whole idea, and it is a strange, wonderful one: instead of accepting the equal-tempered intervals the 950 hands you by default, the 950B lets you dial in each step of the scale by hand. The result is a keyboard that can be tuned to whatever microtonal system you want, one note at a time.
The unit is designed to connect to the 950 Keyboard Controller, and the way it works is elegantly simple. The 950B bypasses the 950's equal-tempered interval control, which is what allows for the individual tuning of each note on the keyboard. Where the stock 950 gives you a single control over the common interval and a manual range control for the whole scale, the 950B replaces that assumption with sixty separate decisions. Owners who have studied the module describe it as a scale programmer "for microtonal use" — a phrase that undersells how radical the thing is in practice. Every note on the keyboard becomes a tuning choice.
The 950B is dated to 1969, and a specific unit bearing serial number 1008 was listed in the spheremusic.com catalog as coming from that year. That is essentially the only dating evidence available. No production run, original price, dimensions, weight, or power requirements have surfaced in any of the documentation consulted. The module is not a synthesizer voice in its own right — it is a control surface, a tuning brain bolted onto the 950 Keyboard — and as such it leaves no audio specs to chase. What it leaves instead is a puzzle: how many were made, and where did they all go?
Rarity is the one thing every source agrees on. MATRIXSYNTH calls it "very rare," spheremusic.com calls it "extraordinarily rare," and Google Arts & Culture, describing the EMEAPP collection's example, simply calls it "Rare R. A. Moog 950-B Scale Programmer." Three independent sources landing on the same adjective is about as strong a corroboration as this module gets. Collectors note that even within the Moog modular community — a group not known for casual ignorance of obscure modules — the 950B draws genuine confusion. A MATRIXSYNTH poster, upon seeing one listed, asked flatly: "Anyone know more about these?" That question has not been answered in any depth since.
Key Features
Sixty Independent Interval Controls
The heart of the 950B is a bank of sixty independent manual controls, each one varying the magnitude of an interval between two successive voltage levels on the 950 Keyboard. Read that carefully: it is not a single tuning knob, and it is not a global transpose. Each control governs one step in the keyboard's voltage ladder, which means the player can stretch, compress, or invert the interval between any two adjacent notes independently of every other pair. The 950 Keyboard itself produces sixty-one discrete voltage levels across a conventional five-octave organ keyboard, so the 950B's sixty controls map one-to-one onto the intervals between those levels. The architecture is a direct, physical answer to the question of how to make a voltage-controlled keyboard play in a tuning system that isn't equal temperament.
Bypass of the 950's Equal-Tempered Control
Normally the 950 Keyboard Controller offers a manually variable common interval — the magnitude of the step between successive voltage levels — along with a range control for the entire scale. The 950B overrides that equal-tempered interval control entirely, which is precisely what allows for the individual tuning of each note. This is the feature that defines the module. Without the 950B, a 950 player can shift the whole scale but cannot break the equality of the steps. With it, the assumption of equal steps is gone, and the keyboard becomes a genuine microtonal instrument. Google Arts & Culture's description — that the 950B "allows the user to modify the tuning of each individual note of a 950 Keyboard" — is the cleanest one-sentence summary of what the module does.
Designed as a 950 Keyboard Accessory
The 950B exists only in relation to the 950 Keyboard Controller. It is not a standalone instrument, not a voice module, and not something that does anything useful without a 950 to plug into. The 950 Keyboard includes the wiring and connectors for the addition of a 950B; the 951 Keyboard, notably, does not. That distinction matters for anyone trying to assemble a working microtonal Moog system today: a 951 will not accept the 950B, so the search has to start with a 950. The module's identity is inseparable from the keyboard it was built to modify, and any collector pursuing one needs to pursue the pair.
Historical Context
The 950B dates to 1969, the year of the one documented unit — serial number 1008 — listed in the spheremusic.com catalog. Beyond that single date, the historical record is thin. No production years, no run length, no original price, and no account of why the module was built beyond its microtonal tuning function have surfaced in the sources consulted. It was an R. A. Moog product, built in the era when the company was still operating under the R. A. Moog name, and it sat in the modular accessory catalog alongside the 950 and 951 Keyboard Controllers, the 958 Foot Pedal Controller, and the 959 X-Y Controller.
One specific unit carries a notable provenance: a 950-B is documented as part of the Buck Owens "Switched On Buck" synthesizer, also located at EMEAPP. That is the closest thing to a celebrity association the module has, and it is a genuinely interesting one — a country music star's synthesizer rig, preserved with its scale programmer intact. Beyond that, the historical trail goes cold. The module's obscurity is itself part of its story: this was a specialist accessory for composers and institutions interested in microtonality, not a mass-market product, and the surviving documentation reflects that.
Collectibility & Value
Every source that mentions the 950B leads with its rarity. MATRIXSYNTH calls it "very rare," spheremusic.com calls it "extraordinarily rare," and Google Arts & Culture labels the EMEAPP example "Rare." That consensus is the most solid fact available about the module's market standing. What is not available is any actual market data: no current prices, no recent sales, no common failure modes, no maintenance information, and no spare-parts availability have been documented in the sources consulted. Anyone considering a purchase is working without a price guide.
The practical advice that follows from the documentation is straightforward. The 950B is a control module that only functions with a 950 Keyboard Controller — and specifically not a 951 — so a buyer needs to secure the pair or accept that the module will sit inert. The extreme rarity means examples surface rarely and documentation is scarce; even dedicated collectors have publicly admitted they don't know much about the thing. The Buck Owens provenance on the EMEAPP unit is a reminder that these modules were installed in real, working systems, which is both encouraging (they were used) and sobering (they were used, and most have not survived). Collectors note that the 950B is best understood as a museum-grade curiosity rather than a practical instrument — a sixty-knob statement about tuning that very few people ever got to make.
Similar items on eBay
No exact Moog 950B listings are live right now — these searches show current Moog and similar vintage synth gear on eBay:
As an eBay Partner, we earn from qualifying purchases. This helps support our independent vintage technology research.