Why use anything but Linear pots?

[smoss469]

Seems to me, from looking at the taper curves etc, that Linear pots are the way to go for almost all applications. A steady increase across the entire range, so why would anyone go for another taper? Seems that the other tapers have the drawback of limiting some of the adjustment so that small adjustments mean huge changes depending on where you're at on the dial.

Am I missing something?

[JaviCAP]

smoss469 wrote

Am I missing something?

Yes, a lot.

[smoss469]

That was very enlightening and informative.

[IvIark]

If you look at something like a gain pot, quite often 85% of the rotation does very little and then in the last 15% of the turn the distortion comes in quickly with little room to fine tune.   Using a reverse log pot instead means that the distortion starts much sooner in the rotation and you get more of the sweep of the pot to adjust and so more resolution.

The opposite happens with a linear volume pot.  The sound gets loud very quickly because of the way our brains perceive audio volume changes, and so if we use a log pot the resistance changes much more slowly so the change in volume is more spread throughout the rotation.

You could quite easily get away with just using linear pots, especially if you're a set and forget person.  But they may not be the best choice if you want better control.

[Geiri]

I'm stocking up on pots now and I order 100pcs of each value every time. Right now I'm stocking up on linear of most used values because I find it the most usable generally BUT it's definitely not applicable all the time. Some circuits just work in the way that a log works better for a smoother control.

It's just a phase now while I'm stocking up, so when I've got loads of 1k, 2k, 5k, 10k, 20/25k, 50k, 100k, 200/250k, 500k and 1M of linear, I'll start doing the same thing with all those values in logarithmic.

[PStevenson]

something else you can do is convert the taper of linear pots - if you don't want to have to buy lots of each.
http://www.paulinthelab.com/2012/07/linear-log-etc-potentiometer-conversion.html

[Geiri]

PStevenson wrote

something else you can do is convert the taper of linear pots - if you don't want to have to buy lots of each.
http://www.paulinthelab.com/2012/07/linear-log-etc-potentiometer-conversion.html

Thanks for that! So if I want to make a 100k log, what do I do? Do you use a 200k pot and a 200k resistor and wire it according to the formula?

[smoss469]

Thanks for the reply IVIark. 2 follow up questions. I know most people seem to be from Europe on here (all the links seem to be UK based stores and UK eBay) but for the US side of the pond:

1) Anyone have a preferred source for decently priced switches, pots and jacks?
2) Anyone know a source for wire similar to the wire Barry sells @ GuitarPCB? Would this be close?


http://www.smallbearelec.com/servlet/Detail?no=85

Thanks everyone!

[dodido]

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[GoranP]

Same here, pretty much on all accounts.

- tayda, can't beat them for shipping prices to europe. Their stuff can sometimes be sub-par but considering that I do this for a hobby, I really don't care.

- barry's hookup wire, expensive to ship to europe but I've found nothing better so far (would love to be proven wrong on this one, so bring it on  )

- most of my wiring ugliness comes from 3pdt wiring so I'm looking to do my own 3pdt daughterboards, just haven't gotten around to doing it. Barry's are fine but I like to include the anti-pop thing with a couple of resistors and a cap. If I ever get around doing that, I'll probably have my pcbs made at some chinese pcb fab house  (with a small kid in the house, I won't be messing with etching and acids like I have in the past).

[Geiri]

smoss469 wrote

Thanks for the reply IVIark. 2 follow up questions. I know most people seem to be from Europe on here (all the links seem to be UK based stores and UK eBay) but for the US side of the pond:

1) Anyone have a preferred source for decently priced switches, pots and jacks?
2) Anyone know a source for wire similar to the wire Barry sells @ GuitarPCB? Would this be close?


http://www.smallbearelec.com/servlet/Detail?no=85

Thanks everyone!

Dude, www.bitcheslovemyswitches.com has the best prices for 3PDTs, jacks and enclosures and good shipping price within the US. I'm in Iceland and I buy from him all the time. He ships same day as well.

[Olav]

Thanks to Paul for that link. Very helpful indeed.