Potentiometer values.

[unclejambo]

Hey,
you'll have to pardon my ignorance in regards to electronics theory here.

I have a gakken which I'm looking to rehouse as one integral unit with a midi if board. While I'm at it I figured I'd brave removing the poxy little trimmer pots and case mounting some decent ones. This would also afford me the sort of spacing that would allow for the big moog style knobs.

Anyhow, on the schematic, some of the trimmers are 50k and the rest 100k. I have some 100k to hand but no 50k. I do however have 47k. How critical is that potentiometer value. If I make the value up with a 3k resistor, am I correct in assuming it would function but with a slightly narrower range of control?

[Circuitbenders]

It'll be more or less identical with 47K. They have a pretty wide tolerance / margin of error anyway so for all you know the 50K one might actually be less than 47K.

Its very difficult to get 50K pots in europe, for some reason they are only available in the US. Try using bigger pots anyway and see if anything interesting happens.

[unclejambo]

Cheers, I had a feeling it wouldn't be a huge issue.

Next silly question, I've gone ahead and removed the trimmers from the board. They look a little like http://img-europe.electrocomponents.com/images/R6916787-01.jpg and I was just wondering how the pins correspond to the pins on a standard pot.

cheers

[unclejambo]

Ok I've read that the centre is the wiper and I can go either way with the other 2. Though this would change the curve on a log pot yeah?

On the schematic I have for the sx-150 it doesn't denote whether the pots are either logarithmic or linear. Am I correct in thinking I would only use log for things like volume and would stick to linear pots on everything else?

[Circuitbenders]

broadly speaking yes, but theres so many exceptions to the rule that it might as well not be a rulle.

You'd have to try log and linear and see which gives you the response you like best

[ScissorFeind]

Its very difficult to get 50K pots in europe, for some reason they are only available in the US. Try using bigger pots anyway and see if anything interesting happens.

I was going through my little parts box and realized I had only 50k's