[sdiy] Analogue Percussion - Anyone know where I can obtain a SN94281 chip?

[steve jones]

Hi All,
I've built 3 Midwest Analogue Products percussion synths: ADV Bass,
ADV Snare and Classic Snare+ and I want to add to them with the Hihat
and Percussive Voice (from the book "Electronic Music Circuits: The
Reprints" by Thomas Henry) -
http://www.midwest-analog.com/cat-book.html

I have a couple of the SN76477 chips, but can't find the SN94281 chip.
Any suggestions where to find this? Or any other Hihat designs - I'm
also looking for rimshot and cowbell voices as well as a simple "audio
to 5v trigger" converter circuit to enable me to use the audio outs
from a TR707 to trigger my MAP drum synths. 

Also, I'm still looking for a schematic for a Sound Master SR-88
Memory Rhythm Machine....

Regards,
Steve Jones,
Manchester, UK.