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Eurorack Knob Idea

(mitxela.com)
311 points po | 2 comments | 25 Apr 25 13:19 UTC | HN request time: 0.45s | source
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adrianmonk ◴[26 Apr 25 04:04 UTC] No.43800846[source]▶
Apologies if I'm missing something obvious, but why not just stick a potentiometer on the same axis behind the 3.5mm TS jack? Many 3.5mm jacks are open on the back, so you can give the knob a long shaft (longer than 3.5mm obviously), and that shaft can mate with the potentiometer.

Alternatively, Eurorack uses TS jacks as connectors for control voltage inputs, right? If you build a module with a TRS jack instead, you have an extra pin (R) that you can connect a removable potentiometer + knob to. And you can still plug in regular TS cables.

(Note: the article uses "TRS" loosely when it means "TS". I mean them literally.)

replies(1): >>43802130 #
1. raphman ◴[26 Apr 25 09:28 UTC] No.43802130[source]▶
Yes, this sounds like a simpler solution - the major drawback/advantage would be that you'd need to insert the knob in just the right orientation so that the shaft end fits into the potentiometer's slot. Might be a bit fiddly. On the other hand, the poti would keep its state even when the knob is removed, and you wouldn't accidentally change the value when inserting the knob.

Just to nitpick the nitpicker: the knob's shaft needs to be longer than 15 mm, right? "3.5 mm" is the diameter, not the length of a small T(R)S jack.

replies(1): >>43805948 #
2. adrianmonk ◴[26 Apr 25 18:23 UTC] No.43805948[source]▶
Oops, yes, 3.5mm is the diameter. I was sleepy when I wrote that, and I knew it didn't seem right.

Good point about the orientation when inserting. I was thinking something like hex or torx or friction fit that would allow you to insert it without thinking about the orientation. But then that causes another problem: any visual markings on the knob aren't guaranteed to be in the right position. I'm not sure if there's a good way get the best of both worlds on that.