Arp Quartet, top octave dividers

Paul R. Higgins higg0008 at
Fri Nov 5 04:00:11 CET 1999

I found a company (Keyboard Systems) on the Net a while ago that still carries 
the old Mostek 50240 and other top octave divider ICs.  They say that they have 
a large quantity of them.  

Point your browser to: 

But ouch! are these chips expensive!  About $40 apiece!

Keyboard Systems also carries some other stuff that may be of interest to list 
members, including MIDI retrofit boards.  I haven't had a good look at these, 
but it appears that they're retrofits for old electronic and pipe organs, to 
make the stops programmable, etc.

Hope this helps.


>     Somewhere in my junk box I should have one of those suckers.  If somebody
> needs one to restore an old piece of equipment, I could see if I could find 
> it.
> I have no idea what condition it might be in, or even if I could find it.

> > <<There is an Arp Quartet on eBay (not mine, I just noticed it), not 
> > working
> >
> > (no sound output, but everything else looks ok-opamp?) -could be a bargain
> >
> > for a DIY'er.>>
> >
> > ...or it could wind up as another white elephant in the attic, if its top
> > octave divider chip has gone bad.  As far as I know, these chips are not
> > available anywhere anymore.  They are a common point of failure in string
> > ensembles.  If anyone knows where they can be purchased, please let the 
> > list
> > know.  (Mostek 50240 and variations thereof)

Paul Higgins
email: higg0008 at
University College, University of Minnesota

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