Arp 4 and 16 Voice Pianos

More info coming soon. I have both the 4 Voice and 16 Voice Arp Pianos and intend to blog repairing them. Currently just probing the s10430 keyer chips in the 4 Voice, suspect I have 2 failed which is the most expensive IC in the piano! Both of mine have multiple failed filter stages, both mute circuits also suspect, output stage in the 16 Voice gone and generally way too much noise in both. In spite of that in my initial testing I love the feel and sound of these, the dual envelope is great, only drawback is lack of timbral variation, maybe it's possible to implement some form of velocity waveform variation with the replacement s10430s.....