Yamaha PS-20 PortaSound Automatic Bass Chord Synthesizer

The Yamaha Portasound PS and PSS electronic keyboards were manufactured in the 1980s and 1990s. In 1980, the low-cost PS-1, PS-2 and PS-3 were launched in a first series. The second series followed in 1981 with the PS-10, PS-20 and PS-30. The name Portasound refers to the portability of the instruments, which are battery-operated. The PortaSound synthesisers were originally designed for children and beginners and often had small keys and simple preset functions suitable for teaching. In 1982, a card-reading system was introduced that allowed players to learn and play along with sequenced songs. Some of the higher end keyboards have advanced features such as programmable synthesiser controls, midi capability and sampler functions.

The PS-20 is a 10-voice polyphonic synthesiser with a keyboard of 49 keys over 4 octaves from C to C. The ROM contains 10 sounds and 8 rhythms, and there is a sustain effect. Sound generation via PASS technology. The Orchestra section offers the basic voicings. The rhythms include March, Disco, Waltz, Rock, Tango, Swing, Rhumba and Samba. A special feature of this section is the 8-bar variation function, which introduces a fill every eight bars. The arpeggiator consists of an automatic chord generator that can generate a major chord, a rhythmic finger chord, a memory chord and a multi-bass chord.