electro harmonix frequency multiplexer Blue BoX?>

[Paul Perry]

At 11:29 AM 30/08/00 -0400, Harry Bissell  wrote:
>Most designs have features that make you think that the original
>designer...
>1) Was VERY clever and is doing stuff so subtle YOU don't notice it
>all...
>~or~
>2) Was an absolute IDIOT.
>I always assume #1 until proven wrong.  In this case I dont know if it
>was planned the
>way it is, or dicked with until it worked... your opinions ???

EH had a couple of designers, and I'd very much like to know their 
histories. I've seen correspondence from one of them, and yes, he 
knew what he was doing. The interesting thing about most EH designs is,
the originality, and the desire to make it as cheap as possible. Plus,
they seem to be designed with weighting to the 'musicality'. Most 
engineers, asked to make a voltage controlled filter, would try for a 
precision rectifier but, look at the Dr Q, there isn't anything precise 
there. So I think there is some 'design by ear', but by people who know
what they are doing. The Dr Q isn't the best envelope filter in the 
world IMHO, but, a lot of musicians disagree with me!
I find the hardest thing in designing fx, is to stop looking at the
CRO and trust my (or preferably somebody elses) ears.

Inventions in most fields occur when someone closely analyses an 
unexpected event. So I think fx boxes might be the same. Some of the 
early wah boxes have such convoluted feedback loops for the tone, that
I cannot believe they arose from mathematical analysis.

Interstage coupling via power supply impedance, is a simple way to 
provide negative or positive feedback overall (depending on the ckt).
If people are making low part count weird boxes, it's woth adding 
'just in case it does somethig interesting' like squegging ;-)

paul perry Melbourne Australia