Engineering:Pianet

The Pianet is a type of electro-mechanical piano built by the Hohner company of Trossingen, West Germany, from the early 1960s to the early 1980s. The designer of the early Pianet models was Ernst Zacharias, basing the mechanism closely on a 1920s design by Lloyd Loar. The Pianet was a variant of the earlier reed-based Hohner electric piano the Cembalet which, like the Pianet, was intended for home use. Hohner offered both keyboards in their range until the early 1970s. The Pianet production consisted of two distinctly different mechanism groups with characteristically different sound. The first group, lasting from introduction to 1977, had ground stainless steel reeds, a pick-up using variable capacitance, and leather faced activation pads. The second group from 1977 until the end of production used rolled spring-steel reeds, electro-magnetic pick-ups, and moulded silicone rubber activation pads.

General description

The Pianet is an electro-mechanical piano requiring amplification to produce a usable sound level. Pianets in the first group of models have 61 keys and a keyboard range of F1 to F6 (43.6 Hz – 1396.9 Hz). The second group have 60 keys and finish at E6 (1318.5 Hz). The keyboard action is very simple. Each key is a single lever element pivoted on a fulcrum point with a spring to return it to the rest position. The key is extended at the rear so that a pad can be mounted over a tuned spring steel reed. This pad adheres to the reed when at rest, and lifts and releases the reed causing it to vibrate when the key is depressed. The vibration of the reed is converted to an electrical signal by a pick-up. The unique playing feel of a Pianet comes from the activation pads adhering to the steel reeds until they reach their point of release.

1960s Pianets

The signature sound of the Pianet, the sound that brought them to prominence and popularity in early 1960s recordings, is the voice of the first production group from the Pianet to the Pianet N and Combo Pianet. This distinctive voice had the presence to cut through the increasingly louder amplified bands of the time. Pianets in this group have bass notes that growl and purr coupled with a bright percussive treble. The sound is complex and warm. The absence of any mechanism to sustain notes in a Pianet means that its sound is generally relatively staccato adding to the ability to stand out in recordings.

In this first group sound is generated by an array of 61 ground stainless steel reeds which are plucked by leather and foam pads saturated with silicone oil. Silicone oil had the benefit of not evaporating from the leather pads, not corroding the steel reeds, and remaining at a consistent viscosity across a wide temperature range. The pads are connected to the keys via metal rods so that, on pressing a key, the pad is raised and released from the reed making it vibrate. An electrostatic pick-up consisting of a segmented vertical plate mounted orthogonal to and just beyond the ends of the reeds transmits the sound to an amplifier. The Pianet's sound was piano-like, sharing sonic similarities to the Wurlitzer series of electric pianos as both relied on metal reeds and variable capacitance as their sound generation source.

Pianet N (Version II). This is a US voltage model sold around 1975 close to the end of production.

Hohner Combo Pianet sold from 1972 onward.

During its period of manufacture the Pianet evolved through a number of model changes. These included transistorised 'solid-state' versions: the Pianet C, and the modernist, lidless Pianet L with metal legs and built in amplifier and speakers. The next model was the longer running and more numerous Pianet N that evolved through two different specifications. The N was fitted with side mounted ‘inverted V’legs and could be equipped with an optional underbelly 12 watt valve amplifier, the Amplifier CP. The Pianet N (version II) was joined by the Combo Pianet in the early 1970s. These were the final incarnations of the first group of Pianets.

The early Pianets (Pianet, Pianet C, Pianet CH & Pianet N) featured lids which opened in an upright V to form a music stand. This feature was introduced on Cembalets and became common to both Cembalets and Pianets. This similarity of appearance results in the mis-identification of models in historic images. The C and N models were equipped with a vibrato circuit operated by a switch mounted next to the keyboard. The Pianet L had no additional effects and used a knee lever to control the volume. The N models used a variable resistance volume pedal cabled to a socket on the rear of the keyboard. The Pianet soon found popularity with music groups of the 1960s, leading Hohner to produce the Combo Pianet model in the early 1970s. It was designed for the performing musician, without legs, and intended to be sat on top of an organ or acoustic piano.

Late 1970s Pianets

thumb|Hohner Pianet T In the late 1970s Hohner produced the second group of models and ceased production of the Pianet N and Combo Pianet. The second group consisted of two models, the Pianet T and M, and a hybrid version combined with a Clavinet, the Pianet/Clavinet Duo. These featured a change in design from electrostatic pick-ups and leather and foam pads to electromagnetic pick-ups (like the Rhodes piano) and silicone rubber pads. The reeds were also changed from the ground finish of the earlier type to a smooth milled finish. This resulted in a different sound, mellower than that of the early models, better suited to the sounds of the late 1970s. While popular with semi-pro musicians due to its low price and portability, the Pianet T made a limited impact on major recording artists. The M model, designed for home use, was built with a wooden console case with internal speakers and a phaser effect circuit. The T model, most commonly found on the used market today, was built for the gigging musician. It had an optional stand and, in a departure from earlier models finished in wood veneer, is finished in black vinyl leathercloth. Its final incarnation came in the Hohner Pianet/Clavinet Duo model which combined a Hohner Clavinet (essentially an electric clavichord) with the Pianet T in one compact (albeit heavy) instrument. Production ceased by the early 1980s.

Models

During the production life of the Pianet the case, mechanical features and electronics changed to keep pace with developments in electronics manufacture, reductions in manufacturing costs, and fashion. Changes to the Pianet were also applied to Cembalet production. Dating the manufacturing envelope and availability of the various Pianet models is confused by misidentification of Cembalet models as Pianets and by the differences in sales availability of models between Europe and the United States. Identification is easy: Cembalet keyboard starts with ´C, Pianet keyboard starts with ´F.

Pianet (Mk.1)

Approximate manufacturing span 1962–1964

Dipl. Ing. Ernst Zacharias, inventor of the Cembalet, Pianet & Clavinet told us the very first Pianet series was called just Pianet. It has a case profile with a taper towards the front. It has tapered cylindrical legs that mount to the underside of the case. It has a gold hammertone painted aluminium fascia panel below the keys. This panel also performs the key levelling function. The keys are injection moulded plastic. The word 'Pianet' appears in gold facing upward on the left hand end of the music support ledge. The ledge includes a formed recess for the bottom of the music. It has a valve pre-amplifier and a knee lever for volume control.

Pianet C & CH

Approximate manufacturing span 1963–1966

The Pianet C has a case profile with a taper towards the front. It has tapered cylindrical legs that mount to the underside of the case. It has a gold hammertone painted aluminium fascia panel below the keys with a lock fitted centrally. This panel also performs the key levelling function. The keys are injection moulded plastic. The word 'Pianet' or 'Pianet C' appears in gold facing upward on the left hand end of the music support ledge. The ledge includes a formed recess for the bottom of the music. It has a transistorised pre-amplifier, a knee lever for volume control and optional vibrato effect.

Pianet L & LB

Approximate manufacturing span 1961–1968

The Pianet L has a stepped rectangular case profile with no lid. It has black tubular steel legs that mount to the underside of the case. It has a black painted aluminium fascia panel below the keys. This panel also performs the key levelling function. The keys are injection moulded plastic. It has a transistorised pre-amplifier and amplifier and a knee lever for volume control. It plays through two small internal speakers or through an external amplifier. Available as model L – mains voltage, and model LB – powered by 5 'D' batteries.

Pianet N

Approximate manufacturing span 1965–1967

The Pianet N has a case profile with a taper towards the front. It has tapered rectangular cross section legs in an inverted V that mount to the ends of the case and are secured by a large threaded knob. The legs are wood grain to match the case. The legs are braced by a gold cross bar towards the base of the rear legs. It has a gold hammertone painted aluminium fascia panel below the keys with a lock fitted centrally. This panel also performs the key levelling function. The keys are injection moulded plastic. The word 'Pianet N' appears in gold facing forward on the left hand face of the music support ledge. It has a transistorised pre-amplifier and a floor pedal volume control. An optional amplifier, the Amplifier CP, was available which mounted underneath the keyboard between the legs. It is a 12 watt valve amplifier with two inbuilt speakers and two inputs, one for the keyboard and one for a record player. Vibrato effect is standard.

Pianet N Console

This variant can be seen on the cover of a Hohner demonstration record for the Pianet. It has an upper case profile with a taper towards the front. It has a gold hammertone painted aluminium fascia panel below the keys with a lock fitted centrally. The keys are injection moulded plastic. It stands on two shaped panel legs joined by a modesty panel. There is a piano-like volume pedal fixed on a timber extension from the modesty panel. The optional amplifier unit available for the N model is mounted underneath the keyboard between the legs. Vibrato effect is standard.

Pianet N II

Approximate manufacturing span 1968–1976

The Pianet N II has a case profile with a taper towards the front. It has tapered rectangular cross section legs in an inverted V that mount to the ends of the case and are secured by a large threaded knob. The legs are satin black. The legs are braced by a black cross bar towards the base of the rear legs. It has a gold hammertone painted aluminium fascia panel below the keys with a lock fitted centrally. This panel also performs the key levelling function. The keys are injection moulded plastic. The word 'Pianet N' appears in gold facing forward on the left hand face of the music support ledge. It has a transistorised pre-amplifier and a floor pedal volume control. Vibrato effect is standard.

Combo Pianet

Approximate manufacturing span 1972–1976

The Combo Pianet has a rectangular case profile and no lid. There are no legs or leg mounting points. Four grey rubber feet are fitted to the underside of the case. It has a gold hammertone painted aluminium fascia panel below the keys. This panel also performs the key levelling function. The keys are injection moulded plastic. The words 'Combo Pianet' are screen printed in black on the left end of the fascia. It has a transistorised pre-amplifier and a volume control knob is fitted at the left end of the keyboard.

Pianet T

Approximate manufacturing span 1977–1982

The Pianet T has a rectangular case profile with rounded corners and a hinged integral lid with central handle. With the lid latched closed the instrument forms its own carry case. The body of the case is covered with black vinyl leathercloth and the ends are padded with vinyl skinned urethane foam. There are no legs supplied as standard. An optional stand can be fixed to threaded mounting points on the ends of the case. The keys are injection moulded plastic over pressed metal frames. The words 'Pianet T' are screen printed in silver on the rear of the case and on the inside surface of the lid.

Pianet M

Approximate manufacturing span 1977–1982

The Pianet M has the Pianet T mechanism built into a rectilinear wood grain console case. There is no lid over the keys. Sitting above the box that holds the playing mechanism is an amplifier housing with a sloped front face and two player facing cloth speaker grills. An acrylic music rest slots into the top of this housing. The leg panels are wood-grained boards finished with a timber foot and joined by a horizontal wood grained panel. The word 'Hohner' is printed in gold centrally above the keys. The model 'Pianet – M' is printed on the amplifier cover panel at the rear. Built in Hohner Modulator, another invention of Ernst Zacharias.

Pianet/Clavinet Duo

Approximate manufacturing span 1978–1982

This hybrid model uses a black case in the style of a Clavinet E7. The Duo has a rectangular case profile with rounded corners and a removable lid to protect the keys and control surface for transport. Samples can be found with both versions of the name: Pianet Clavinet Duo and Clavinet Pianet Duo. The control panels at the left hand end of the instrument include keyboard splits and mixtures of the two instruments as well as normal Clavinet mixture controls.

Users

Early Pianets were used on a number of hit recordings from the 1960s and 1970s, including "She's Not There" by The Zombies; "Louie Louie" by The Kingsmen; "Summer in the City" by The Lovin' Spoonful; "I Am the Walrus", "Getting Better", "The Night Before", "Tell Me What You See", "You Like Me Too Much" by The Beatles; "This Guy's in Love With You" by Herb Alpert; "These Eyes" by The Guess Who; and "Joy to the World" by Three Dog Night. In the glam rock era, the Pianet was used by Bryan Ferry on the first few Roxy Music albums, for instance featuring prominently in their hit Editions of You. It was a staple of the "classic lineup" sound of Curved Air (1970-1972), featuring prominently on their first 3 albums, played by both guitarist/keyboardist Francis Monkman and violinist Darryl Way. The 1972–74 lineup of progressive rock pioneers King Crimson used a pair of Pianets in live performance, played both by the group's violinist David Cross, and the guitarist, Robert Fripp. Tony Banks of Genesis used one prominently on the group's first four albums, as a lead instrument through a homemade fuzz box and to simulate piano sounds onstage.

Fleetwood Mac's Christine McVie was a noted proponent of the Pianet N and Combo Pianet from the first group of products. In an article written by Bob Doerschuk in the October 1980 issue of Contemporary Keyboard she outlined why she preferred the sound of the 1960s Pianets and why she eventually replaced them.

The Pianet is enjoying a renaissance (e.g. Bugge Wesseltoft's Change) due to its unique sound and the availability of new pads for the earlier models, most of which had been reduced to unplayability due to pad decay. It is also popular as a substitute for the Wurlitzer electric piano, which has a similar electro-mechanical mechanism for generating sound but is typically much heavier, requires more maintenance than the Pianet, and is overall more expensive.

Restoration issues

For two decades in the 1980s and 90s replacement parts for Pianets became progressively harder to find because they were no longer being supported by Hohner. The principal problem was the activation pads for the first group of Pianets, the 1960s instruments. Urethane foam was used as the damper behind the leather surface of the pad. The urethane decomposed with age, making the pads unusable. Hohner intended the pads to be a service-replaceable item (like the strings of a guitar). Restorers and players who wanted to keep a Pianet working were obliged to manufacture their own pads. The second group of Pianets, the T and M, used silicone rubber for their pads. They have aged extremely well and are still functional in most keyboards, as of 2012. The silicone pads of the T & M are not suitable for the 1960s Pianets. Their adhesion properties don't suit the ground reeds of the first group of instruments, and they produce a static discharge that is amplified by the capacitive pick-up of the instrument. In the 2000s, a number of businesses took up the servicing and maintenance of vintage keyboards, so pads suitable for both groups of Pianets are now available.

The mechanical structure of keys, pivot rail, reeds, reed bar and pick-up are the same in the 1960s Pianets from the "Mk.1" and C to the Combo, so spares to get a Pianet working can come from most models. While the electronics differ from model to model, they can be exchanged if the aim is to make a keyboard playable rather than to restore it.

References

• "Robert Fripp's Diary: Tuesday, 15th September 1998". Archived from the original on 13 October 2014. https://web.archive.org/web/20141013205400/http://www.dgmlive.com/diaries.htm?entry=1592. 

Bibliography

• Vintage Synthesizers by Mark Vail, Backbeat Books, 1993 & 2000, ISBN:0-87930-603-3 – Chapter on Electric Pianos, Harpsichords & Clavichords of the 50s & 60s by Barry Carson.

External links

• Pressed+metal 2003/228/1 Electric keyboard, Hohner Pianet, timber / metal / plastic, designed by Ernst Zacharias, made by Hohner AG, West Germany, 1962–1970 Powerhouse Museum, Sydney, Australia
• Detail pictures of a Pianet T and a Cembalet.
• Manufactures replacement pads for all Pianets
• Manufactures replica replacement pads for group one 1960s Pianets C, L, N (versions I & II), Combo Pianet.
• Contemporary Keyboard (10/1980), Christine McVie