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Having recently refurbished an early '70s ADM console (thanks, Tom!), I can state fairly firmly that the Slidex, which used a twisted piece of aluminum activated by the slider to turn a conventional Allen Bradley pot, was pretty crude, and very difficult to match mechanically, channel to channel.

Teac/Tascam in their Series 70 mixers used a string to turn a standard rotary pot, if memory serves, this was much better.

Steve


On Apr 12, 2012, at 11:08 AM, Tom Fine wrote:

> http://www.google.com/patents/US2517180?printsec=drawing#v=onepage&q&f=false
> 
> Art Davis worked for Cinema Engineering, which was marketing a form of this kind of attenuator in 1953 and probably earlier.
> 
> See:
> http://www.preservationsound.com/?p=4611
> (I provided the scans, from old magazines)
> 
> As we know, slide-faders became the preferred interface for analog mixing boards, eventually replacing rotary faders in almost all applications (although small-format mixers sold by companies like Behringer, Mackie, Alesis and others still use rotary faders). There have been many varients on slide-faders over the years. In the 60's, Fairchild sold a fader that controlled the intensity of a light source, which then interacted with a LDR to control gain, branded "Autoten." In the 70's, Audio Designs & Manufacturing (ADM) patented a mechanical system that drove a pot that controlled a VCA to control gain. The advantage of the ADM "Slidex" attenuator was that liquid (perhaps coffee at a TV station, beer at a radio station or something more exotic at a recording studio) could spill across the slider section of the console and not short out anything, within reason.
> 
> Here is the Slidex patent:
> http://www.google.com/patents/US3736801?printsec=drawing#v=onepage&q&f=false
> 
> -- Tom Fine 

Stephen Anderson
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