TequilaKez Posted May 14, 2006 Report Share Posted May 14, 2006 I dug up my old midibox that I never finished and decided it would be nice to get it working.Only thing is the sliders I bought are 50K. I've been told they should work with a minor modification but I have no idea what. Quote Link to comment Share on other sites More sharing options...
eufex Posted May 14, 2006 Report Share Posted May 14, 2006 It should work if you connect your pot in parallel with a resistance of around 12.5K. Quote Link to comment Share on other sites More sharing options...
moebius Posted May 14, 2006 Report Share Posted May 14, 2006 Hi.If those are 50K linear sliders, those should work ok with no modification. Using pots with more resistance than 10K might introduce AIN jitter which is best fought using short cables between pots <-> AINs and AINs <-> core and maybe shielding.Connecting parallel resistance is a bad advice as this will result resistance curve to bend from linear response.Moebius Quote Link to comment Share on other sites More sharing options...
audiocommander Posted May 17, 2006 Report Share Posted May 17, 2006 here ya go: http://www.midibox.org/forum/index.php?topic=6506.0try an additional load resistor of ~7k and tell us if you got it going... ;)Connecting parallel resistance is a bad advice as this will result resistance curve to bend from linear response.Isn't every standard AIN-10k-Pot connected parallel? Or does this apply only to non-10k-resistors? ???Michael Quote Link to comment Share on other sites More sharing options...
smashtv Posted May 17, 2006 Report Share Posted May 17, 2006 Isn't every standard AIN-10k-Pot connected parallel? Or does this apply only to non-10k-resistors? ???MichaelAny time you add a resistor to a pot it changes the response curve or taper....Depending on the values involved this could mean that your pot acts more log than linear........In the real world this translates to a fader where 1cm of movement in the middle might range 10 values, but 1cm at the bottom or top of the throw may only range 5 values.....That's why its not so good advice, accuracy and feel are lost. You can't fly it without looking at the display if the taper is very far from linear.BestSmash Quote Link to comment Share on other sites More sharing options...
audiocommander Posted May 17, 2006 Report Share Posted May 17, 2006 Any time you add a resistor to a pot it changes the response curve or taperAhh, I see!As I'm working with sensors most of the time, I haven't noticed this, because it's hard to measure the linearity of my own finger pressure ;DKewl to know that..Thanks,Michael Quote Link to comment Share on other sites More sharing options...
moebius Posted May 17, 2006 Report Share Posted May 17, 2006 What happens when You don't press it? You need a "load resistance"? If your work includes mostly Midibox and samples from "Spectral.." I'd like to know how Your findings add up here..Moebius Quote Link to comment Share on other sites More sharing options...
audiocommander Posted May 18, 2006 Report Share Posted May 18, 2006 actually I was referring to my FSR-sensor, which I adore. Though somewhat unspectacular, they are very well playable - good responsiveness; and with a proper tested load-restor-value astonishingly accurate to control - altough they also return to the inital state on release (but it's easy to store and retain the last value by code if necessary). It has instrumental qualities since I learned how to finecontrol my finger pressure :)I have mixed feelings about the spectral distance resistors. :-\ They are quite impossible to order here in germany, so I have only some samples. Some of them (8cm, 10k) are very good to use, one 360° round pot makes troubles, because it creates a short on one special point, the other one does not show this behavior. Using them as "encoders" needs some lines of code. I don't know yet if it's worth the pain, because:All of them need to much pressure for my taste and that makes it difficult to get a smooth response. The touch-distance-pot as seen in the Electribes has a much better responsiveness (threshold), but I have no clue where to get them. :-\I have also one with 15cm legth, that must be damaged, because it keeps snapping back to a middle value on release, wich makes it unuseable.First I wanted to use them as volume-controllers (along with LED-Levelmeters as state indicators) but for absolute or visual controlling they are not suitable. For pitch or modulation / intuitive audible controlling purposes they are ok. I thought they were cheaper and cooler than motorfaders, but the spectra stuff is really expensive for small amounts, too.Because most of them don't have 10k but rather 8k or 47k, I need these load resistors, otherwise the AIN-measures go crazy; and it's true, now that I know it, I can see a slight nonlinear behavior. But it's tolerable, because they're not made for accuracy anyway and artistically spoken, I'm more interested in making music "controlled by ear" and therefore try to reduce the visual interface as much as possible. ;)Michael Quote Link to comment Share on other sites More sharing options...
stryd_one Posted May 18, 2006 Report Share Posted May 18, 2006 While I was working on the MBFX stuff I stumbled across this logarithmic response from having a resistor parallel to a pot... If anyone wants to see lots of pretty graphs and ugly math let me know and I'll send you a MS Excel file with my findings...Of course there is one way around it... Use two variable resistors in parallel and find a way to vary the resistance on both of them simultaneously... Quote Link to comment Share on other sites More sharing options...
Rowan Posted May 18, 2006 Report Share Posted May 18, 2006 ........Dual ganged pots in parallel ;)Rowan Quote Link to comment Share on other sites More sharing options...
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