Hi,
I need a 500k motorized slide pot for a project and am having trouble finding them online. It's hard enough to find motorized ones in a more common resistance, although I'd think they'd be commonly available for use in mixing desks. Can anyone point me in the right direction?
Thanks,
Zach
Do you mean something like this:
http://parts.digikey.com/1/parts/738103-pot-slide-500k-ohm-1-10w-20mm-vt-448xc2504bdn.html
Yes, except motorized. Also, at 1.441" long, that one is really tiny.
Just a thought, maybe it's time to check out digital pots?
It will be used manually as well, so a digipot isn't an option.
In some quick searches I did, two companies seem to come up for "motorized slide potentiometers": ALPS and Panasonic.
Yes, these are mainly for mixing decks, but they always seem to be 10K only (and fairly expensive; one I saw for sale at DigiKey was $40.00+!).
I don't think you are going to find a 500K motorized potentiometer for sale anywhere; you could probably get something like this custom made by ALPS or Panasonic, if you were willing to spend the $$$ to do it.
You might have better luck "rolling your own"; you would need to use a very low friction slide-pot, then build a back-driveable transmission (likely belt drive) to a motor.
If I were doing this, I would likely use small toothed belts and pulleys, and use tape capstan motors for the actuator motor. The slide pots I would use would be a long-lever type, and I would hook the lever to the middle of the belt (split belt). I would also add a quadrature encoder to the motor, so that I could sense movement (and direction) in manual mode and provide "power movement" to the slide pot. Also, perhaps a hall-effect current sensor on the motor to detect end-of travel and operator force.
Doing all of that would likely end up costing more than $40.00+ per potentiometer, though; but certainly less (maybe) than what ALPS or any other company would charge to build it custom...
Yeah, I've seen both Alps and Panasonic ones and couldn't find anything above 10k either.
$40 is fairly typical for motorized pots and both those companies make very high quality pots in general- often they're true log taper, which always commands a certain price. I've even seen regular non-motorized pots that cost over $100.
I don't really have much interest in rolling my own, as these are for an audio application and need to be of superior quality.
After much searching and posting to another forum, I was finally able to find a regular motorized pot at 500k (from potentiometers.com- go figure), but decided I'd rather use a slide pot for greater visual feedback. I figured finding a slide version in a broad range of values would be easier because of their application in mixing desks, but so far no dice. Do they all just use 10k because they're digital and can map it to any analog value they want?
Do they all just use 10k because they're digital and can map it to any analog value they want?
Probably; even if they were staying analog, they could still "map" the range needed using other parts (amplifiers and such)...
How exactly would they do this analog mapping? I can't really think of a method that would preserve decent audio quality.
How exactly would they do this analog mapping? I can't really think of a method that would preserve decent audio quality.
Honestly, I don't know; maybe I am making a big (and wrong) assumption? It just seems to me to be possible (although maybe it would make things worse as you said).
Analog electronics has always been a fair mystery to me; something almost like "magic" - I've never been able to get my head around it except for the basics (and RF? Fuggedaboutit).
;D
I'm basically using this to replace the volume pot on a guitar, which is almost always either 500k or 250k.
What I was referring to regarding the audio quality was any method that would let you simulate a 500k pot using a 10k one (like compressing the signal, then amplifying it on output).
I should have been more specific: I was planning on using this as a rheostat.
I'll do a test hooking a guitar up to a 10k pot. Can you elaborate on how impedance factors into choosing potentiometer values? I've read that guitars typically have between 1M and 500k.