Blending between two capacitors?

[azrael]

Is it possible to create a control that allows you to sweep between two capacitor values? Say .01uF and .1 uF? I think I've seen it before..

I want to build another Rangemaster, and have a variable input cap again, but I want a cleaner setup than a 6-way rotary switch.

[Derringer]

this'll probably do it



try maybe 250KB for the pot ... see how well it mixes between the caps and go from there

[panterafanatic]

why not make the sweep lug be the output? have lug 1 and 2 be caps, and the center lug be output, its what i'd do.

[Derringer]

that would work  ... but you'd be introducing more series resistance to your input signal if set up that way

[panterafanatic]

but you still have the .01 uf. doesnt capacitance ad in parallel? not like it'd be a huge issue. but just a thought.

[Barcode80]

the layout above would only add a variable amount of the .1 to the .01. That means you are always running through the .01. the smoothest and easiest way is as mentioned after, which is to connect each cap to the outside lugs and use the center lug as the output.

[Derringer]

yes, capacitance does add in parallel

and I thought the point was to be able to vary the capacitance, to go from a relatively lower capacitance to a relatively greater capacitance

If you use the pot as a blend, as has been suggested, you'll be altering more than just the capacitance, you'll be adding series resistance ... and maybe that is a non issue, but it will affect the interaction of the preceding signal on the following stage (affect in a good/bad way is for the user to decide)

With the design that I posted you will still get some series resistance but it will be less severe and will be more uniform as you turn the pot as compared to using the pot in a "blend" configuration.

The only right answer is to try them both and see if you like the way one sounds better.

[StereoKills]

Or.....you could use a variable capacitor.

[frequencycentral]

Or like this? http://www.ilovefuzz.com/download/file.php?id=2080&t=1

[yodude]

Lots of seemingly relevant info in this thread:
http://www.diystompboxes.com/smfforum/index.php?topic=53374.0

[azrael]

Lots of seemingly relevant info in this thread:
http://www.diystompboxes.com/smfforum/index.php?topic=53374.0

I think that'll do the trick! thanks.