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View Full Version : switch vs. pot


tjs
06-29-2007, 09:43 AM
I'm thinking of building a highly switchable tone stack for the purpose of experimenting with different component values without having to swap parts in and out. I was wondering what the pros and cons are of using a switch for this purpose verses a potentiometer.

For instance, I would like to be able to select slope resistor values of roughly 56k, 100k, and 150k (33k would be nice too, but I can't think of an easy way to add that as an option). The two simplest ways I can think of doing this are as follows:

1) Wire 100k and 150k resistors in parallel and use an on/off/on switch to shunt either or none of them. 100k//150k would give me 60k.

2) Wire a 56k resistor in series with a 100k linear pot. With the pot all the way down I have 56k, at 12:00 I have 106k, and all the way up I have 156k.

The first method would take up less space and the second would give me gradual rather than stepped control of the slope resistance. Would one be preferable to the other in terms of less added noise and signal degradation?

Swarty
06-29-2007, 10:03 AM
How about a rotary switch with all the values you want?

scottl
06-29-2007, 10:32 AM
I believe that would be similar to something like the curve switch on the Pure 64 amp. What style circuit is the build?

How about a rotary switch with all the values you want?

tjs
06-29-2007, 11:32 AM
How about a rotary switch with all the values you want?

:jo

I am indeed an idiot.


What style circuit is the build?

I'm not entirely certain yet. It will be my first, so I probably don't want to get too complicated with it, but at the same time I'd like to build something I can use and I've got the "simple Fender circuit" thing covered already.

I'm leaning toward this one: http://www.londonpower.com/kits/gpk.htm. Not the simplest circuit in the world, but it's the preamp section only, the instructions should be pretty decent, and it sounds like a good circuit to experiment with mods/tweaking.