FS: Refurbished ARP Omni I

[Mark Smart]

I just finished totally overhauling this beast. Here's what all I did:

1. Replaced ALL of the 22uF tantalum caps in the keying circuitry (not just
the ones which were bad). These are the caps that cause the "stuck notes"
problem for which the Omni is famous. I replaced the original tantalums
with high-quality non-polarized electrolytic capacitors which are rated for
50V rather than the 35V of the originals. The logic behind this was to use
caps which are more impervious to transient overvoltages and voltage
reversals than the original caps. All this together means, in all
likelihood, another 20 years or so of use with no stuck notes.

2. Performed Timothy Smith's modification on the 4075 filter module for
increased cutoff frequency range of the filter. This made a very noticeable
improvement.

3. Replaced all op-amps in the output VCA section, as well as a bad LM301
op-amp which was disabling the envelope generator.

4. Tweaked and tuned everything following the intructions in the service
manual.

I realize that the Omni I has a reputation for being inferior to the Omni
II, but this is not entirely deserved. Since I've had both around recently
to play with, I've been able to compare fairly objectively.

Okay, admittedly the Omni I's chorus doesn't sound as good as the Omni II's
and it has less flexibility in terms of interfacing. But there are a couple
of things I like better on the Omni I:

1. The "synthesizer bass" voices get routed through the same filter as the
poyphonic synth section, not through a separate unchangeable filter as on
the Omni II. This allows for more kick-butt bass sounds since you have
direct control over ADSR and LFO modulation of the cutoff frequency. This
allows, among other things, a duplication of the cool machine synthesizer
sounds at the beginning of Pink Floyd's "Welcome to the Machine"! 

2. The "Master Volume" slider is really a master volume! On the Omni II,
the master volume slider is actually a "volume of everything else except
the bass voice" slider, which is totally stupid, if you ask me.

Just thought I'd make my case for the underrated Omni I.

This particular one is in pretty good cosmetic condition, but sorry, it has no
slider caps. I am asking for $350 or best offer. 

************************************************
*     Mark Smart                               *
*     Network Technician                       *
*     University Communications Inc. (UCI)     *
*     smart at medusa.nn.com                      *
************************************************