[sdiy] Analog Computer vs. Modular

[John L Marshall]

An analog modular synthesizer is similar to an analog computer.

Decades ago I used an analog computer at Boeing in Renton, WA. If remember
correctly, the room was about 40 feet by 40 feet with analog modules
covering three of the walls. Coefficients were "programmed" with resistors
and capacitors mounted on dual banana plugs. Other coefficients were set
with those big 10 turn pots.

Consider that an intergator is a low pass filter, a differentiator is a high
pass filter. Many of the other modules are similar.

I also had a Heathkit analog computer (the small one). I think that it was
nothing more than 5 operational amplifiers with a bunch of patch pin
connections on the front panel.

Take care,
John
www.sound-photo.com
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----- Original Message -----
From: "Czech Martin" <Martin.Czech at Micronas.com>
To: "Sdiy (E-mail)" <synth-diy at dropmix.xs4all.nl>
Sent: Wednesday, February 19, 2003 5:35 AM
Subject: [sdiy] Analog Computer vs. Modular


> Because of the biz trip I'll loose another two weaks,
> oh well...
>
> (such a trip is usually NO FUN. Even business class seats
> will make your back ache after some hours. I can not sleep
> in planes, and usually you can not look down to the ground.
> Analog Computers usually contain integrators,
> coefficient modules, sometimes nonlinear functions,
> sometimes multipliers, etc.
>
> Modular Synths can have that, too. But
> built into special functional blocks.
>
> Has anybody ever seen a module set that comes
> close to the old analog computers, i.e.
> enables to program some differential equation
> and the like?
> It is perhaps challenging to provide integrators
> as stand allone units because of the high
> impedance input that would require (at least for dc).
> It is perhaps more challenging to have the time
> constants voltage controlled (well, OTA).
>
> I could imagine a little "sytem in the system",
> where a local set of such analog computing gear
> is stuffed into a module, the patch field
> for tiny, short wires usually covered with a metal shield
> (a plastic transparent but conducting shield would be cooler
> but nothing for DIY I fear...).
>
>
> m.c.
>