Chorus mod, clock capacitor changes

[Zben3129]

I know that changing the cap in the clock part of the circuit can change (drastically) the sound of the chorus, and I was browsing futurlec and came across http://www.futurlec.com/CapTrimmer.shtml

First off, does this do what I think it does? As you turn the trimmer it increases the capacitance in a linear fashion?

And secondly, if this comes in a trimmer form, does that mean it could be a pontentiometer somewhere?

Would this be usable for the cap (47pf stock) in a chorus? There is a trimmer with a 10pf-90pf range



Zach

[Mark Hammer]

If you thought caps had wide tolerances, try trimmer caps!

Not sure if they show a picture of the device, but it is unsuitable for use in any fashion other than like a kind of PCB trimpot.

When chorus pedals with variable delay range are designed typically, the way they work is to provide a kind of DC offset voltage that is summed with the LFO.  Far easier to implement.  Take a look at the schematic for the venerable Boss BF-2 to see how it is done.

[Zben3129]

If you thought caps had wide tolerances, try trimmer caps!

+/- 175% 

Thanks for the reply, and I figured there were just trimmers as thats all I could find.

I'll look into the other variable delay range idea


Zach

[StephenGiles]

I have variable trimmer caps that I bought from Maplin - there you go - they do sell something useful!!!. One is used for the %^&* cap on my ADA Flanger, needing a small screwdriver to make the adjustment. I suppose one could superglue a small screwdriver to it and devise a panel control arrangement, but it probably wouldn't stand up to use on the road.