[sdiy] 2164 4P LPF board for sale

[David G. Dixon]

I've had three positive responses, and am giving rights of refusal in the
order in which they arrived, so it's probably gone.  If not, I'll be back...

> Hey Team,
> 
> (With apologies in advance for posting an advertisement to SDIY...)
> 
> I have a fully built and tested four-pole lowpass filter board based on
> cascaded 2164 VCAs and integrators which I built to serve as the core of a
> Oberheim-style multimode filter.  It also has inverted outputs at each
> stage
> for eight quadrature sine waves at self-oscillation.  And, as I've
> discussed
> here before, it has distributed resonance gain (using an extra 2164 --
> this
> gives equal sine wave amplitudes without sacrificing equal signal
> amplitude)
> with the "reverse exponential" response for a smooth approach to
> oscillation.
> 
> I've panelized it, tested it, calibrated it and even used it in a jam
> seesion, and it works perfectly.  It has a cutoff frequency range from
> about
> 4 minutes to about 25kHz, three CV inputs, coarse and fine cutoff adjust,
> resonance, resonance CV, adjustable zener voltage (from about +/-5V to
> about
> +/-10V), a 3-input mixer with mixed (unfiltered) output, and multiple
> stage
> outputs and with two spare cross-connected 5-pin connectors for easy
> connection to any multimode interface.  It features all 1% resistors, four
> 1% silvered mica 205pF filter caps, machined IC sockets, 18-turn trimmers,
> 0.1" off-board connectors, and a standard MTA-156 power connector (MOTM
> format).  It's handmade (well) with tinned traces, and is a compact 4" x
> 5".
> 
> All this can be yours for the cost of the parts: CDN $45 + $5 shipping =
> $50.  I'll ship it anywhere in the world.
> 
> Why am I selling it?  Because I want to build another one with a slightly
> different layout incorporating two slight modifications: an extra trimmer
> in
> one spot (totally not needed but I'm a bit obsessive), and an extra opamp
> to
> convert one of the CV inputs into the +/- format that we've been
> discussing
> here over the last few days.  Of course, the latter could easily be added
> by
> hanging the opamp off a pot chiclet (a la the Grenader Gizmotron) but I
> hate
> doing that.
> 
> If I don't sell it, I will probably cannibalize it for parts, but that
> seems
> a shame, since it's only had about 2 hours of actual playing life.
> 
> Please respond privately if you're interested, and I can send photos, etc.
> I use PayPal.
> 
> (We now return you to our regularly scheduled programming...)
> 
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