The Good Knob (and Pots + Encoders) Thread


Trying to find 25mm encoder both for Ambika and Shruthi, STEC12E08 from Reichelt and 1520813 from Farnell are 20mm and don’t fit with the plexi case. Also read somewhere that with 30mm knob rise a lot, it’s that true? Thanks in advance…


I always use the Reichelt 20mm part and put something (M3Nut - or a piece of Aluminium Foil from my TinHat™ )int the knob.


i will try with the nut, but I will never strip down my Tinhat!


The go rob a Kaugummiautomat


Whoa, these still exist in your neighbourhood ?
Here in the Mainhattan area they ceased a long time ago, due to vandalism…


I have one on the backside of my house on the Veranda…


@shiftr: The “L” or sometimes as "Shaft Length L” used in manufacturer part numbers refers always to whole length, being from bottom of casing to the end of the shaft.
Sometimes you´ll find “height”, this would refer to the casing height.


Alps usually takes just the lenght of the shaft. And bourns seems to take hight from the pcb


I would always try any alternative to Alps, because they last, well, not long.
Alps uses the descriptor LM¹ for the whole length and l¹ for the part of flatted shaft length.
Other manufacturers usually use t or T instead of l (L).


The statement about Alps is really true. In my programmer one of them didn’t even survive pushing the knob onto it. They really plastic stuff ! Bourns are way better.


I don’t have any problems with Alps. There are cheap Alps and expensive Alps i guess you get what you pay for.


I have a Bourns plastic shaft pot on my Turing Machine and it is garbage: this one
Wiggles around so, so, so much. I have liked Alpha the most in my experience.


@joshuagoran: Yes, these PTV09A Series you´ve linked to, wiggle from day 1, but I would prefer wiggling ones for a year heavy use, than non-wiggling ones which send ghost data to any given controller after 5-6 months of heavy use.
For the Bourns , it´s better to use only the ones with a sleeve, plain plastic sleeve if not panel mounted with hardware, they won´t wiggle over time, right now Mouser has only the sleeveless wiggle pots from PTVA09 in stock.

Best pots are still the ones with at least 15. - 30.000 cycle/turns life, usually with metal case and shaft.

There are some reliable cermet pots from “BI Technologies”, they will last a good time, but will wiggle a bit too (over time).


Tried paper, aluminum, and the nut… the knob “dances” and don’t like the feel. Need to source 25mm ones.


@elhambre: if you can get 30mm ones if they are known to fit and known to be “good”, as to not wiggle/knob dances, then you can cut 10mm away, as others had suggested before.
For the Ambika you can get the ALPS RK09D1130C2P 25mm from Mouser

Also, I have not explained well myself above about ALPS pots.

The pots which ALPS produces today and the ones fitting into Shruthi and Ambika control-pcb´s footprints are to avoid for long term durability.
In other words, all ALPS pots fitting into Ambika+Shruthi footprint are “cheap” in terms of durability.

ALPS also has not a wide selection for pots as Bourns has, but ALPS has very good faders.


Thanks @MusicCircus but i was talking about encoders, anyway i will do that get 30mm encoders and cut away.


Oh yeah, sorry, now re-reading it a 3rd time I saw it ^^.
PEC12R-4025F-S0024 but without detents


These are the knobs being used on the touchdigital imposcar2 controller. Originally I was thinking about getting that wellcrafted device for miscellaneous controlling purposes. After being told the controller wasn´t built anymore, I thought about creating a custom controller. Well, at least I already got those in my eyes beautiful looking and also very well feeling knobs + potis. :slight_smile:

They are 19mm in diameter and 18mm in height with a full circle 5 mm shaft.


hi guys,

this one is really “low profile” and im happy to share this source for the most fantastic knobs and potis/ encoders with you:

they have great great endless encoders without clicks and the knobs they have are simply amazing.


Great link FG445! - lovely to see some different pot knobs for a change.