Lesser Known Facts About the Minimoog Model D

The Minimoog Model D is often described as the first truly portable analogue synthesizer to define modern electronic music. These are some lesser discussed details that help explain why it became so influential.

You probably have the Minimoog Model D to thank for every top hit that was ever sent up the charts in every genre and decade since its creation. The Minimoog Model D has gone down in history as the most iconic     classic synthesizer of all time with its inspiration reaching a multitude of artists, across a spectrum of genres, spanning decades across its production lifetime. Impossible to imitate, the Minimoog Model D set the bar so high in electronic music history, that competition found it a tough act to follow, let alone imitate.

Why the Minimoog Model D was a game changer

Created in 1970, the Minimoog Model D was the instrument that brought the synthesizer out of audio university labs and professional recording studios and placed it in the hands of experimental progressive musicians all over the world. In contrast to the larger room-filling modular analogue synths of the time, the Minimoog Model D was far more accessible and could be played instantly, with no cable-patching between modules. Everything the performer needed was within hands-reach right there on the front elevated panel. The real true genius of the Minimoog Model D was the design of the front panel. By consolidating and grouping related components – Controllers, Oscillators and Modifiers the front panel quickly became a visual, easy-to-understand signal flow chart that made audio synthesis more accessible and comprehendible unlocking experimental creativity for musicians. The Minimoog Model D was soon lovingly embraced by a diverse and genre-rich roster of performers. Over the course of just over a decade, there were well over 10,000 Minimoog Model D     analogue synths sold across the world. Even today, some 50 years after its release, the Minimoog Model D remains one of the most highly regarded, influential and coveted classic synthesizer in electronic music history.

Bill Hemsath

Although the spotlight of the Minimoog Model D's success often falls on the company founder Robert Moog, it was Bill Hemsath, an engineer at RA Moog C who began to investigate the concept and possibility of creating a smaller instrument with preset sounds, that he strongly believed would be more appealing to musicians. 

So in 1969, Hemsath began Frankensteining a prototype using spare parts with no specific plans or objective. He dug out a broken keyboard that he found, saw off the top octave and kept the lower three. He took the hybrid keyboard and custom fit it into a small wooden cabinet with just a small series of wired patches. The result was the 'Min A' the Minimoog’s very first prototype. But Robert Moog didn't consider the 'Min A' anything more than an experiment, however, Hemsath sensing a turn in the industry and instrument market he continued to invest time into the project and working with other engineers Jim Scott and Chad Hunt they evolved the Min A into the Min B, which also now came installed into a suitcase. Although Moog hadn't completely endorsed the work by Moog and saw no commercial value, he allowed his employees to continue developing the instrument into what was becoming the 'Min C'.  

At this particular time, the company was facing a downturn in sales. Moogs early modular synthesisers were losing appeal with musicians. Finding sounds using patch cables was proving a time-consuming and uncreative process. The large, room-filling instruments were also very temperamental and would typically go out of tune with the slightest change in room temperature. So faced with an attic filled with spare parts and the potential of closure, engineers turned their focus back to the Min C project but this time without Moog's blessing or support. They very shortly produced a range of small instruments they called the Model D. Mogg was entirely happy and understandably perceived the Model D as an engineering mutiny, but realising that this Minimoog could possibly save the company he began to come around and went ahead with production.

Design decisions that shaped its sound

Although nearly 50 years old, the technical innovations of the Minimoog Model D were far advanced for their time and ahead of whatever their competitors were producing. The Moog ladder filter with its unique and distinctively designed 24dB/4-pole became the sound that its competitors tried to emulate. The Minimoog Model D filter was filled with character, evolving from sweet to harsh tones it's a sound that catered for every musical eventuality.

The overdrive-headphone loop

Due to circuit technology being in its infancy some 50 years ago, the original Minimoog Model D provided very little in the way of saving patches and so instead invited experimentation. It was through this musical endeavour, that the legendary overdrive loop was born where the headphone output would feed back into the external input. The result was an inspirational distortion now affectionately known as the overdrive-headphone loop.

Why it still feels relevant today

There's no arguing that the Minimoog Model D has a unique and characterful sound, but you may not know that this was born entirely out of an engineering accident. Moog engineers struggled to find a solution to stabilise the power supply of the instrument resulting in the three oscillators drifting out of phase. This flaw of engineering is what led to the unique, rich and warm sound the Minimoog is most famous for. The voltage-controlled filter featured on the Minimoog Model D was also created entirely by accident. engineer Jim Scott had accidentally overdriven the Model D's filter, which generated that powerful and recognisable filter sound that the Minimoog is renowned for. All of these happy accidents went completely unnoticed until the instrument was already in production. The decision to simply leave the design alone is what made the Minimoog Model D the diverse and expressive instrument that it is today.