The QY20 is a
portable sequencer released by
Yamaha in
1994. It has 8
tracks (4 for sequenceing and 4
accompaniment tracks (2 chord, bass and drums (8 different
drum sets are available))).
For the sequencer you can use 100 different
voices (guitars, brass, strings and many others) which can be recorded in
real time- or in step-mode. The QY20 has an 1
octave keyboard included, but for home use you can plug any
MIDI keyboard (even with attack dynamics (I hope this is the right word, if not please msg me the correct one) or any other MIDI device in. Unlike the QY70 it can not output complete songs directly, but has a MIDI output.
According to http://www.prepal.com/data/yamaha.htm the orginially 650 $ expensive device, which is now out of production can be purchased for round about 150$ when used.