[sdiy] Question how to improve rotary encoder feel

[paula at synth.net]

Roman,

ooo, I like!!

Paula

On 2017-06-09 15:02, Roman Sowa wrote:
> That description is exactly what that pot is, I mean the picture
> Julian posted. At first glance it looks like regular pot, but it has 2
> wipers rotated by 180 degrees.
> And here's my DIY attempt to make such pot from regular cheap dual pot:
> http://www.synthdiy.eu/files/endlesspot.jpg
> 
> Roman
> 
> W dniu 2017-06-09 o 13:49, rburnett at richieburnett.co.uk pisze:
>> The Ion pots are available from Alesis as replacement parts for repair
>> work.  Perhaps you could buy one to play with, then see if there is 
>> any
>> manufacturer's info on it to suggest if it's made by one of the usual
>> suspects like Bourns, Alps, Alpha, etc...
>> 
>> I don't have an Alesis Ion, but an engineer friend who has one 
>> explained
>> the operation of the pots to me like this:
>> 
>> Dual track potentiometers, except one track is rotated 180 degrees
>> relative to the other track, and no mechanical end-stops so they can
>> rotate continuously.  When the wiper for one track goes over the
>> discontinuity in its track, the other wiper is in the middle of its
>> track.  Some clever software is then used to read the voltages from 
>> both
>> wipers and "hide" the discontinuities in each track by using data from
>> the other track at that time.  You then get smooth high-resolution
>> parameter adjustment with endless rotary control, and free from any
>> glitches or mechanical detents.  That's the theory anyway, perhaps 
>> some
>> Ion users can comment on how well it works in practice?  They've been
>> around for a while now, so it would be interesting to know how well 
>> the
>> well-used pots are holding up!
>> 
>> I hope that explanation made sense.
>> 
>> -Richie,
>> 
>> 
>> 
>> On 2017-06-09 12:26, Julian Schmidt wrote:
>>> I found 2 pics of the ION parts
>>> http://studiorepair.com/gallery/Alesis/Ion/slides/Alesis_Ion_Potentiometer__STUDIOREPAIR_04032501_1510157530.JPG
>>> 
>>> http://studiorepair.com/gallery/Alesis/Ion/slides/Alesis_Ion_Panel_PCB__STUDIOREPAIR_04032501_1510087626.JPG
>>> 
>>> 
>>> julian
>>> 
>>> Am 09.06.2017 um 13:17 schrieb Julian Schmidt:
>>>> I'm all ears if you know a part number or source for affordable
>>>> endless pots.
>>>> All I can find are expensive industrial ones in the >10€/piece range
>>>> and although being 360° endless rotation parts, the resistive taper
>>>> spans only 340°
>>>> The Ion pots look more like the normal, cheap 1-2€ pots but my
>>>> research turned nothing up, yet.
>>>> 
>>>> julian
>>>> 
>>>> Am 09.06.2017 um 12:53 schrieb rburnett at richieburnett.co.uk:
>>>>> You could look at using continuous rotation pots like the Alesis 
>>>>> Ion
>>>>> supposedly uses.
>>>>> 
>>>>> -Richie,
>>>>> 
>>>>> 
>>>>> 
>>>>> On 2017-06-09 11:30, Julian Schmidt wrote:
>>>>>> Hello All,
>>>>>> 
>>>>>> I have a current idea that could vastly benefit from using 
>>>>>> encoders
>>>>>> instead of pots.
>>>>>> My only gripe is that I never had an encoder where I liked the 
>>>>>> feel.
>>>>>> With the standard 24PPR encoders you have to make way too many 
>>>>>> turns
>>>>>> to get to a higher value.
>>>>>> Rotationspeed based value speedups made the feeling even worse on 
>>>>>> the
>>>>>> machines I tried. Also a lot of people complain about encoders on
>>>>>> synths for the same reason.
>>>>>> Best solution so far is something like on the midibox or AN1X 
>>>>>> where
>>>>>> you push the encoder for fine resolution.
>>>>>> 
>>>>>> The only one people seem to like are the Nord ones with the LED 
>>>>>> rings.
>>>>>> I never had a nord machine in my hands, but Forum research 
>>>>>> suggests
>>>>>> that they somehow managed to line up the LED movement on the ring 
>>>>>> with
>>>>>> the encoder travel. So if you turn the encoder half a rotation, 
>>>>>> the
>>>>>> value LED is at half, too.
>>>>>> 
>>>>>> Any idea how they've done this? looking up the specs it seems like
>>>>>> they are using Bourns ECW1D-C24-SE0049L encoders
>>>>>> (http://electro-music.com/forum/topic-50251.html).
>>>>>> 49L is not specified in the datasheet, but my guess would be 48L 
>>>>>> =>
>>>>>> 48PPR which would still be too little resolution to even bring a 7 
>>>>>> bit
>>>>>> value up to full range in one revolution.
>>>>>> Is the front panel resolution just reduced and interpolated on the
>>>>>> nords?
>>>>>> 
>>>>>> So if anybody has some hints how to give an encoder a more
>>>>>> potentiometer like feeling I'm all ears. Especially if we talk 12 
>>>>>> bit
>>>>>> instead of 7 bit parameter resolution.
>>>>>> 
>>>>>> For practical reasons encoders would be great for layered UIs to 
>>>>>> share
>>>>>> a set of controls between multiple LFOs or preset saving. LED 
>>>>>> rings
>>>>>> are sexy as hell, too. But whenever I use encoders for something 
>>>>>> other
>>>>>> than menu diving and editing settings I wish for a pot in my hands 
>>>>>> ;)
>>>>>> 
>>>>>> Cheers,
>>>>>> Julian
>>>>>> _______________________________________________
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