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.

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.

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.

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