[sdiy] Omni chorus

[Gene Stopp]

I had an Omni once - boy did that thing piss me off. The keying-or-something
capacitors for each key started going bad one by one, so every time I'd turn
around there would be another stuck note. So I cannibalized it and jumped up
and down on the circuit boards. Of course I did this after I scavenged:

* A nice 49-note Pratt & Read keyboard
* A +/-15 volt nicely regulated power supply
* An ARP potted VCF module to replace a bad one in an Odyssey
* Some replacement sliders to add to my ARP parts stash
* The chorus board which I turned into an effects box

I honestly don't remember if I got the TOG chip out - if it was a 50240 then
I would have definitely grabbed it and put it in the chips drawer.

The chorus board is great. Run a D-50 or OB-8 into it, and you can get some
pretty thick stuff going on. It is definitely too noisey to bring up on a
Front-of-House PA, so I added a simple noise gate. Don't think I ever wrote
down the schematic, however.

I would say that $50 is good for the keyboard assembly, alone.


Best Regards,

- Gene

-----Original Message-----
From: Tim Parkhurst [mailto:tparkhurst at siliconbandwidth.com]
Sent: Thursday, December 18, 2003 1:52 PM
To: synth-diy at dropmix.xs4all.nl
Subject: [sdiy] Omni chorus


So here's a question for the group: If I can get a semi-working ARP Omni (Mk
I) for about $50US, would it be worth the effort to gut the thing for the
chorus unit? Basically would it be worth it in terms of sound quality, and
the effort required to remove the chorus circuitry and add voltage control
to some parameters. I could yank that circuitry out, put it behind a modular
panel, and still have the top-octave chips to play with. Whaddaya all think?