Ernst Zacharias & The Hohner Clavinet

Ernst Zacharias poses with a selection of his creations at the Eboard Museum in Klagenfurt, Austria. Photo: Ulrike Muehlbachler

Ernst Zacharias invented the Clavinet and has spent a lifetime perfecting electro-mechanical instruments. We talk to him about his life and explore his classic designs.

The Hohner Clavinet is one of the most sought-after vintage keyboards, its unmistakeable sound a presence on countless classic recordings from the late 1960s onwards. Less well known, however, is its inventor, Ernst Zacharias. A couple of years ago, I was living in the Netherlands and working as a specialist in vintage electric pianos. I was asked by the Dutch Clavichord Society to deliver a talk on the Clavinet to their 25th anniversary symposium in Leiden in Holland. The secretary informed me that one of the society’s affiliates, a clavichord builder based in Oldenburg in the north of Germany, knew someone who used to work at the Hohner factory. This former employee turned out to be none other than Ernst Zacharias himself! My contact agreed to drive me to meet Zacharias at his home in Hamburg, and act as interpreter during the interview.

Approaching his 90th year when we met him, Zacharias lived alone in a modest two-room apartment in an elderly residents’ complex. But it was obvious on first meeting him that age was no barrier to his work as an inventor of musical instruments. Even before our interview began, Zacharias was keen to talk about one of his latest projects: a dynamic organ, complete with pipes and vibrating reeds. He produced one of his prototype notes and proceeded to give us a demonstration, blowing into the pipe to get sound. Since our interview a patent has been awarded to Zacharias for this invention.

The Organ Maker

“It all started with my great love of Bach,” were Zacharias’ first words in answer to my question about his path to becoming an inventor. He was born in 1924 in Neumunster, a small town around 40 miles north of Hamburg, one of nine children in a musical family. His father was into the new technologies of the time: he owned a car, and in 1928, the family were among the first in the town to own a radio. Zacharias’ mother played the harmonium, and marked the listings with a red pen when there was to be any Bach or Mozart on the radio. By this stage the young Ernst was supposed to be learning the organ, but he spent more time tinkering with projects than practising.

His mother was the daughter of a carriage-maker, and it was with the assistance of this family business that Zacharias was able to build his first organ keyboard in 1948. For the tone generators, he used valves that had been developed in secret during the war for the Wehrmacht. “Every key self-built,” he explained proudly. Zacharias also mentioned building a monophonic pedal-tone generator which was designed as a bass accompaniment for a piano. Eventually he went to Kiel University to study electrical engineering, subsequently working as a telecommunications engineer with the Deutsche Post.

Zacharias’ first journey to the Hohner factory in the southern German town of Trossingen involved an interesting connection with pre-war German electronic music. From the 1920s, Jorg Mager had been one of the main pioneers of microtonal electronic musical instrument design, having developed instruments such as the Spharophon, the Partiturophon and the Kaleidophon. Mager died in 1939, and none of his instruments survived the war, but it was his son Siegfried who accompanied Zacharias on this long journey. Siegfried had developed the Multimonica, a strange hybrid of accordion and monophonic synthesizer, on which Zacharias worked during his early days at the Hohner factory. Initially, they were part of a college trip, planning to visit the Varta battery factory at Hagen and the Ford plant at Cologne, but Zacharias and Siegfried Mager left the main group and carried on through the Black Forest to the Hohner factory.

After this trip Zacharias was in regular correspondence with Hohner’s director and was very keen to join the company, although the management initially thought they had no role for him. Eventually, in 1954, they agreed to employ him. When he joined he recalled the directors joking about how hardworking “us Swabians” were, as Zacharias was a newcomer to Trossingen from 500 miles further north in Germany. At 7am each morning a hooter sounded to mark the beginning of the day for the 5000 or so Hohner employees.

Shanghai To San Francisco

In the 19th Century, Hohner, through their sales of accordions and harmonicas, had grown into one of the world’s biggest musical instrument manufacturers. In 1929, Hohner accounted for nearly 60 percent of all German exports to the USA, and had a worldwide network of offices extending to pre-revolution China. Combined with this global success, Hohner’s status as the main employer in Trossingen also meant that the directors enjoyed considerable influence in local politics. But as the 20th Century progressed, the management did little to reform Hohner’s chaotic supply chain, and as technology evolved, their sensitivity to consumer taste began to desert them. To add to this, in the Second World War, the factory had been commandeered by the Nazis to produce military equipment, mainly detonators. So, by the time Zacharias joined Hohner, the company were in a state of post-war flux, trying to reorganise while attempting to keep pace with the new amplification technology marketed by its more efficient and culturally aware American competition.

The consequence of the eventual failure of Hohner to adapt is that their product base has today retreated to their acoustic roots, and is mostly produced in the Far East. Only the highest-quality Hohner products are now handmade in Germany. But when Zacharias joined the company, they were still major global players, with all Hohner products manufactured in Trossingen by a workforce at the peak of its size. According to Zacharias, the ethos of Hohner during his time there was to widen access to music by making affordable versions of traditional instruments, a pattern which is very much in evidence in his designs, as well as their names. The focus on popularising music extended to the music school in Trossingen, today known as the Hohner Konservatorium, which was run by Hohner and used partly to promote their products. Alongside his work as an engineer, Zacharias taught acoustics in the school for 12 years.

There was also an emphasis on ensuring that the aesthetic design of Hohner instruments was not out of place with post-war contemporary furniture styles, which explains the retro look of the keyboards. Mid-interview, Zacharias pulled out a folder of brochures for his instruments to illustrate this. He explained that he wrote most of them himself, as well as the liner notes on the various demo records that were produced by Hohner for his instruments.

In terms of their internal construction, however, Zacharias’ instruments were often innovative. Hohner’s use of synth-style metal keybeds and modern plastics technology was in contrast to the American electric piano designs, where wooden keybeds, and a wooden piano action in the case of the Wurlitzer, persisted into the 1980s. Sometimes, however, the use of the latest materials tended to compromise longevity, as anyone who has worked on a Hohner electric piano will testify. Some components were so prone to decay that there was a long period when nearly every model was rendered unusable, until remanufactured parts became available in the mid-2000s. Nevertheless, today Zacharias’ instruments, in the hands of a skilled technician, can be made as reliable and playable as when they were new. In some cases aftermarket modifications have extended their capabilities.

The Hohner Clavinet

The first Zacharias-designed instrument to be put into production by Hohner was the Cembalet (see box). Its success and that of the Pianet helped overcome some initial scepticism from the management about his ideas, and Zacharias was granted more freedom to experiment. Eventually he led a team of electronic and mechanical specialists to develop his more ambitious designs.

In the interview we were able to hear the Clavinet as its inventor had intended it to sound. By the window in Zacharias’ apartment stood a pristine Clavinet L — the rare triangular, reverse-keyed Clavinet — with a copy of Bach’s Two Part Inventions on the stand.

The first prototype of the instrument that would become the Clavinet was named he Claviphon. Both visually and mechanically it was more similar to traditional clavichords.Photo: Gerd Prix

Mounted on top were stereo speakers, self-built and incorporating an in-built phase shifter. The stereo phasing was, Zacharias informed us, an important part of the sound, which was otherwise very clean and far from the kind of overdriven auto-wah Clavinet beloved of most enthusiasts.

The first prototype of the Clavinet was the Claviphon. Completed in 1961, its action more closely resembles that of a conventional clavichord.

The strings are mounted above the keys on a metal harp. When a key is depressed, the anvil at the end of the key shaft presses a hammer up through a hole in the harp into the string, sounding a note. The keybed appears to be identical to that found in a Pianet N.

Ernst Zacharias’ own prototype Clavinet has stereo speakers that, he says, are an important part of its sound.

In the Clavinet, which began production in 1964, the action is inverted, which makes it a truly unique instrument. The strings are mounted on a metal harp under the keybed, and a rubber hammer underneath the front of each key presses the string against a metal anvil mounted on the harp structure. This aspect of the design in particular interested the clavichord builders and enthusiasts at my talk: though there have been countless variations of the clavichord, none is configured in this way.

The rare and early Clavinet I variant, resplendent in brown wood veneer!

Zacharias stated that the reason for this design change was that he liked to play with greater force than the Claviphon prototype would allow, and therefore needed the greater stability of fixed anvils. It is interesting that in various patents for the Clavinet, the instrument is often referred to as being “in the style of a clavichord”, in spite of the design change. One patent even refers to the design as an “improvement” over the clavichord.

In contrast with the capacitance pick-up used in the Claviphon, the Clavinet used two electromagnetic pickups — in effect, giant guitar pickups — which could be polarity-inverted for different tones. The keybed was changed to use the same key mouldings that were used in the later Pianet T.

The sound of the Clavinet reaches the listener through two huge electromagnetic pickups, akin to giant guitar pickups.

Finding A Home

Although the first Clavinet demo record began with performances of Bach, Schumann and Mozart, the early Clavinets were roundly rejected by classical musicians. It was not until 1967 that the Clavinet sound began to emerge on commercial recordings, and the earliest examples came from unexpected genres. The Clavinet appears to have begun its extensive film score career that year, on the soundtrack to Jerry Goldsmith’s In Like Flint. It also is used on a reggae recording from the same year called ‘Attractive Girl’, by the Termites. The jazz, funk and disco pedigree of the Clavinet is very well documented elsewhere; the earliest Stevie Wonder recordings are from 1968, notably ‘Shoo Be Doo Be Doo Da Day’, preceding the classic multitracked Clavinet milestone ‘Superstition’ by four years. The Clavinet was also used in folk music to good effect by Triona Ni Dhomnail, keyboard player of Irish group the Bothy Band, who used a Clavinet L extensively in the 1970s, as well as a Baldwin Electric Harpsichord.

When I asked Zacharias if the success of the Clavinet had come as a surprise to him, he answered no. The Hohner engineers were aware of the versatility of the Clavinet in a band environment, which can be heard on the band recordings on the early Clavinet demo records. Zacharias was also well aware of the presence of Hohner in the USA market, and their ability to promote the Clavinet there. But in spite of the ubiquity of the Clavinet sound on recordings and the respect it gained amongst musicians, the Clavinet was only a minor part of Hohner’s output. Around 38,000 units were produced in a run lasting almost 20 years. This compares with a total of 250,000 Rhodes pianos manufactured, for example. Eventually the tooling for the Clavinet was destroyed by Hohner, and any remaining parts for the keyboards were sold off in bulk.

One of Ernst Zacharias’ major innovations in designing the Clavinet was to position the harp and strings under the keybed, rather than above it.

Nearly 20 years after its introduction, a patent awarded to Zacharias in 1983 showed that development of the Clavinet at Hohner was ongoing. The text of this patent explains that the sound of the hammer contacting the anvil in the Clavinet was seen as undesirable. To solve this problem, Zacharias moved the hammer behind the anvil so that when a key is depressed it stretches the string over the anvil rather than directly making contact with it. This mechanism would also in theory give greater possibility for pitch bending — ‘bebung’ in clavichord terminology — which, being restricted by the nature of the Clavinet action, is possible to achieve, but difficult to integrate into a performance.

By this time, however, the rise of digital synthesizers and the changing sound palette of 1980s pop music was leading the Clavinet sound to fall out of favour. There are tragic tales of instruments simply being taken to the dump.

Owning A Clavinet Today

Up until the last 15 years or so, it was still possible to buy a Clavinet very cheaply, but values began to rise in line with the return to popularity of 1970s funk. Today a Clavinet D6 in good condition can fetch anywhere between £1200 and £2000. The later E7 model can often be purchased for less, as even though it has a superior preamp to that of the D6, it just doesn’t quite look the part. The Clavinet C, as used on Stevie Wonder’s ‘Superstition’, is rare. Even rarer is the Clavinet L, as described above.

There are other variants, too. The early Clavinet models I and II sometimes come up for sale; the Clavinet II is the better buy, as it shares the tuning mechanism with the later Clavinets. The Clavinet I has strings wound directly to the tuning pegs, and therefore needs a steady hand to be tuned well. The Clavinet Duo is a curious hybrid of a Clavinet E7 and a Pianet T, with the option of splitting registers or layering the two keyboard sounds. In spite of the greater versatility of the Duo, the Pianet section tends to interfere with the speed of the Clavinet action, so the Duo does not feel quite as direct as a straight Clavinet. There were various other models of Clavinet, including plexiglass versions mostly manufactured for top players, and notably Zacharias’ own DIY version. The production model was expensive, so he built a Clavinet for himself out of spare factory parts, which now resides in the Eboard Museum in Austria.

Tuning a Clavinet I using these screws requires a steady hand! Later models improved this aspect of the design.

In terms of repair issues, Clavinets are prone to a variety of problems. The most well-known is that the original hammers soften with age, to the point where they have to be scraped out of the hammer holders and the residue cleaned off with acetone. Clavinet pickups are also prone to cracking, most often at the mounting points, as the outer plastic casing goes brittle with time. Most Clavinets have a hairline crack in the pickup, which will cause the internal wiring to break if it becomes too large. Sometimes the epoxy resin inner casing can be scraped away to enable the wire to be resoldered, but a new pickup will usually be the only reliable solution. This can get expensive. Restringing is difficult and time-consuming, and tensioning the damping yarn correctly requires real skill, though Vintagevibe now sell a gel-based damping kit which makes a full restring less of a chore. There are various aftermarket preamp upgrades possible for the Clavinet, as well as different grades of hammer tips and strings manufactured by different companies.

The most interesting modification of all for the Clavinet was developed in the 1970s. The Castle Bar mod, invented by Buddy Castle, is in effect a giant Clavinet whammy bar. The strings are all mounted on a rotating bridge, connected to a rod protruding from the lid of the Clavinet. The player presses down to the rod to bend the pitch. This radically alters the playability of the Clavinet, making it into a powerful lead instrument. There are videos of George Duke using a Castle Bar Clavinet in live concerts in the early 1980s. The Crash Kings’ recent video The History of the Guitar With No Guitar shows all the possibilities of the Castle Bar Clavinet as a lead instrument. Ken Rich Sound Services are now producing an upgraded reissue of the Castle Bar mod which irons out the quirks of the original.

By The Wayside

An examination of Ernst’s patents, all of which can be viewed online at the German patent site depatis.net, is the best way to get an idea of how prolific he was. He has patents awarded over almost 60 years, from 1957 for an organ tone-generator system up to 2015 for an aspect of his dynamic organ design. Beyond the electric pianos discussed above, he has been awarded patents for instruments such as the Guitaret, a button-operated electric lamellophone; and the Claviola, a blown keyboard instrument which uses reeds in pipes for tone generation. In addition, he has patents for many modifications of instruments such as keyed recorders, an additional acoustic clavichord design, numerous harmonica variants and a synthesizer keybed. There are even patents under his name for a bicycle and an aircraft, as well as for the pendulum clock on his wall that chimed throughout our interview.

With the keybed turned upside-down, the hammers that give the Clavinet its distinctive sound are visible.

Gert Prix, the curator of the Eboard Museum in Austria, also has around 100 pages of logs that Zacharias made during his time at Hohner. The sample page that he translated for us give a sense of the routine of work in his department at Hohner, and is fascinating in the various instruments listed that never made it into production. Entry 103362, dated 9th October 1969 is: “Make a Clavinet to place on top of organs as a second or third manual. Furniture-style design with optional legs.” In red pen below this entry it states: “Parts of this instrument were transferred to a subsequent order Clavinet A number 103366 dated 12th March 1970.” Could the Clavinet A have been some precursor to the C and the D6?

Entry 103358, dated 4th September 1969, states: “Making of an electronic toy piano. Aborted attempts without satisfactory result. Waiting for a new keyboard action with longer key travel.” Entry 103352: “Cembalet P (Pianet P). Colonial-style case with front legs. Kept at Zacharias, delivered with components to USA 12th March 1970.” Possibly this style of case was requested for the USA market and was intended for both the Cembalet and Pianet. But no Cembalet P or Pianet P was ever produced.

The most often encountered variant of the Electra Piano is the ‘console’ model. This example is from the collection of leading repair specialists Electric Piano Service, based in the Netherlands.

Last Years With Hohner

When Zacharias turned 65, he got into trouble with the Hohner management for working past the retirement age. At that point he went to work for the Italian organ manufacturer Bontempi, where he continued to be awarded patents. This move was not successful, and he was eventually able to return to work for Hohner for a further seven years. He talked to us about his frustrations with the salesmen (“kaufleuten”, in Zacharias’ words) mentality of the new management, and their ‘Swinging Hohner’ marketing campaign of the period. It would be easy to assume that someone with such a prolific career and such wide influence as Zacharias would have had ample financial reward for his work. But we understand from Gert Prix that Zacharias had rather a low pension from Hohner, and was by no means wealthy in retirement.

Following our interview, Zacharias took us into his workshop, which also doubled as his bedroom. The entire room was filled with instrument prototypes. Anyone who has ever taken the lid off a Zacharias-designed Hohner instrument would recognise the style of everything in this workshop, even down to the wiring. As well as various lengths of pipes from his dynamic organ, there was a single-note prototype for a dynamic harpsichord complete with quill and string, and another harpsichord-type instrument where the strings were activated by pads coated in magnetic lacquer. We were enthralled for another hour as he continued to explain more of the principles behind the dynamic organ. In fact he was far more enthusiastic about showing us his continuing work as an inventor than dwelling on his previous achievements. It would have been privilege enough to meet him just to review his career as we had intended to do, but to see his workshop, and his lifetime’s experience inventing still very much active, was truly inspirational.

The Hohner Pianet

The Hohner Pianet (this is the T variant) acquired the reputation of being a poor man’s Rhodes, but a well-maintained instrument can sound very good.The Pianet is best seen as a variation of, rather than a replacement for, the earlier Cembalet. The two keyboards have different registers and were produced concurrently into the 1970s. The Pianet activates its metal reeds with a foam-backed leather pad soaked in silicone oil. This gives the instrument a minimal dynamic range — at least more than the Cembalet. Unfortunately, the foam backing of the pads tended to literally turn to dust, meaning that every Pianet needs replacement pads in order to be able to make any sound at all. Zacharias filed a detailed patent for this design, which though apparently very simple, has proved extremely difficult for modern electric piano parts manufacturers to duplicate. Reissue pads either come as a solid piece of silicone, a design which fails to heed the warnings in the patent of the necessity for a soft foam core to prevent clicking; or as an attempt at an exact copy of the original, which, though capturing the authentic sound, doesn’t last as long as it should.

The Pianet came in different variants. Apart from the Combo Pianet, which was a stripped-down version released in 1972, most were designated by a letter: N, C, CH, L and LB. In the 1970s, Zacharias redesigned the Pianet to get closer to the sound of the Fender Rhodes. He changed the single-piece electrostatic pickup for individual electromagnetic pickups, and the reeds for mild steel in order that they could be magnetised. The pads were redesigned as a single piece of silicone, which activated the blued reed surface through suction. Zacharias still has the moulds for these pads. This new design came in two variants: the M, a rare console model with built-in speakers, and the T, which is one of the most widely available electric pianos and often regarded as the poor man’s Rhodes. This mechanism, unfortunately, is notorious for sounding weak and uneven, due to degradation of the pad surface over time, and a tendency for the reeds to rust if stored in even a slightly damp environment. However, the reissue pads for the T and M are pretty effective as long as the reeds are degreased and any rust removed.

The early Pianet is quite close in sound to the Wurlitzer electric piano, and was played by many of the top bands of the 1960s. The Beatles used it extensively on the album Help, as well as on ‘I Am The Walrus’. The Zombies also used a Hohner Pianet on many tracks, including ‘She’s Not There’, one of the most famous Pianet records. Christine McVie of Fleetwood Mac also used a Combo Pianet extensively for live work.

The Electra Piano T has a unique mechanism which offers unparalleled touch-sensitivity.

The Hohner Electra Piano

The Electra Piano is one of Ernst Zacharias’ lesser-known keyboards and very rare in the UK. A patent for the action design was awarded to him in 1969, and the diagrams show what is in effect a fusion of a Rhodes and a Wurlitzer. It has individual tuning fork-style tone generators, but with a reed instead of a tine. Each assembly is mounted on rubber, and an electromagnetic pickup is mounted on a section of the tonebar which bends down to the side of the vibrating end of the reed. This can be bent towards or away from the reed to determine volume and dynamics. The action design is very similar to that of a Rhodes, with the hammer cam sliding over strip of felt on the back of the key as the key is depressed. A screwhead protruding from the back of the hammer cam can be adjusted from a slot in the rear of the case to set the escapement.

The Electra Piano has a few design flaws, the most significant being the dampers: as they damp directly onto the free ends of the reeds, they tend to wear out as the vibrating reed cuts the felt to pieces. The upper reeds tend to lose sustain, possibly due to the degradation of the rubber mountings, which are difficult to replace. After changing the felt dampers for a more durable material (rubber or even leather are more appropriate), and voicing the pickups, the Electra can a beautiful-sounding piano. The instrument was used on some famous tracks: the Beatles’ ‘Come Together’ has a brief Electra solo, and Led Zeppelin used one on number of tracks including ‘Stairway To Heaven’. Chick Corea can be seen playing an Electra Piano on stage with Miles Davis at the Isle of Wight Festival in 1970. The British jazz fusion band Nucleus used one more extensively in the early 1970s, on their albums Elastic Rock, We’ll Talk About It Later and Solar Plexus. The definitive Electra Piano recording features the British jazz pianist Gordon Beck playing a long solo introduction to ‘Ariadne’ on the Nucleus album Labyrinth from 1973. Here, we encounter in full the gorgeous harp-like quality of the Electra.

Even rarer (and arguably prettier) than the console version is the portable Electra Piano T.

There was also a portable version of the Electra Piano called the Electra Piano T, with a radically different action and harp from the console Electra. The action of the T has a unique feature: as the hammer is raised by the key, the main body of the hammer is stopped against a fixed bar. A separate tongue with the hammer tip mounted on it then flips up to strike the reed. This system gives far more touch sensitivity than in the console Electra, and hints at a new dimension of compact electro-mechanical piano building. Zacharias was awarded a patent for this design in 1973.

Unfortunately, the Electra Piano T was not a success, which explains its extreme rarity. There is a possibility that this involved a lawsuit with Rhodes, as the design has many similarities. One story we heard from a student of Gordon Beck was that Beck had an endorsement from Hohner to use the Electra Piano. He devised his own portable chopped version of the Electra, which he claimed Hohner copied for the T. When he was presented with the factory version he was so disgusted with the way his design had been adapted that he gave up playing Hohner instruments and from then on used Rhodes pianos instead.

As well as instrument designs, Zacharias received patents for his single-decker and double-decker gliders!