The Electra-Piano was a series of electric pianos built by the Hohner company of Trossingen, Germany from the 1960s to the 1970s (not to be confused with RMI's all-electronic ElectraPiano of the same period). Internally, the Electra-Piano is similar to both the Rhodes and Wurlitzer pianos: It has striking hammers (like the Rhodes) and a vibrating metal reed to create the sound (like the Wurlitzer). The model is built in the style of a small spinet piano, with a valve amplifier and four loudspeakers mounted inside. The instrument was cumbersome for live performances, with its wooden casing more like heavy, solid furniture, and was not too portable. It's sound was also not clear live.
'Stairway to Heaven' on Led Zeppelin's fourth album, is their most famous track, and the Electra-Piano is played in a supporting role beginning at 2:14. John Paul Jones played directly into the console and using the Hohner for the piano chords with his left hand playing bass. The part is very subtle, a supportive texture underneath the guitar tracks that follows the chord progression. Following 'Stairway to Heaven' is 'Misty Mountain Hop', a bouncing heavy rock song that is based around a strong syncopated Electra-Piano riff. The riff continues throughout the song and is heavier sounding than the 'Stairway to Heaven' piano, as it was recorded through its amplifier and loudspeaker, not directly to the console.
Led Zeppelin's most obvious 'keyboard' song comes from the Houses of the Holy album. Beginning with a long electric piano instrumental, 'No Quarter' was Jones' featured solo section in the live show for many years. The Hohner is processed through an EMS VCS3 synthesizer to create a 'wobbly' sound. In concert, Jones extended the song with lengthy improvisations and duets with Jimmy Page on guitar. 'Down by the Seaside' on Physical Graffiti, is another Electra-Piano song, with Jones playing a traditional country-pop piano arrangement.