Discussing the EQ

[VacuumVoodoo]

I'm still searching through my pulp based archives for it. It will no doubt surface when I'll be looking for something else

[Donner]

I'm still searching through my pulp based archives for it. It will no doubt surface when I'll be looking for something else

ah or maybe you just THINK its there ... its Pulp Fiction

[BJF]

Hi,

In anchient times files were kept in ink ......this was before the head of IBM came along and stated that the market for computors in the world could be about three......
Files were kept in ink when one envisioned computors to in the future weigh only a mere 3 tons.
Files were still kept in ink when computor were nomore competent than the scientific calculator you can buy at a supermarmarket.

Files are still kept in ink as they are swifty drawn......

Somewhere I have some drawings too we shall see. However Off the top of my head I made a parametric EQ with OP amps manny years ago and used and inverting OP amp to control gain and then set up a State Variable Filter as a tuneable filter within the feedback loop of the first OP amp and for this to work for symmetrical boost and cut it had to have a gain equal to 1. As Q also sets the gain of the SVF I had a dual ganged pot to control a small range so spread would negliable one part setting gain at input so filter wouldn't overload and the other setting Q and another dual ganged pot to set the frequency range also this one setting a small range. Loking at the spread of potentiometers linear potenitiometers have much less spread than any other curve and if building but one one can select.
Arguably it is much more precise to switch components......and that also works repeatedly.
Right but then one could think of other filters that one could use......ink file ahum.............

Have fun
BJ