←back to thread

Eurorack Knob Idea

(mitxela.com)
312 points po | 5 comments | 25 Apr 25 13:19 UTC | HN request time: 0s | source
Show context
bondarchuk ◴[25 Apr 25 14:06 UTC] No.43793707[source]▶
>It's a nice dream, of a synthesizer where any knob can be pulled out and replaced with a patch cable, and any jack can have a knob plugged into it to set it to a fixed value.

What's even better, though, is a coupled knob + jack where the knob turns into an attenuator for the input when a cable is plugged in, and works as a standalone knob otherwise. I think this is quite a common design.

I believe I've also seen patch cables with built-in attenuators.

replies(3): >>43795371 #>>43796910 #>>43798608 #
1. kennywinker ◴[25 Apr 25 16:18 UTC] No.43795371[source]▶
Another common pattern is jack + offset. The most useful is when you have jack + offset + attenuator… but most modules pick one or the other for space reasons.
replies(2): >>43796120 #>>43796260 #
2. BlandDuck ◴[25 Apr 25 17:11 UTC] No.43796120[source]▶
Totally. Also, an attenuator is easier and cheaper to implement, because it just requires normalizing V+ into the jack plug. An offset requires an adder.

My preference is: attenuator < offset < attenuator + offset. I see no benefit of having to remove the knob to get to the jack as proposed in the article.

replies(1): >>43798503 #
3. robotresearcher ◴[25 Apr 25 17:23 UTC] No.43796260[source]▶
The attenuator-inverter is super handy too. A gain knob that goes from -1 to +1 X.
replies(1): >>43805609 #
4. nine_k ◴[25 Apr 25 21:04 UTC] No.43798503[source]▶
The benefit is saving space. Imagine a 10x10 grid of such jack / knob inputs.
5. wbl ◴[26 Apr 25 17:43 UTC] No.43805609[source]▶
That's a neat trick. Only way I can think of to do it involves two op amp buffers, one inverting one not and take the signal from the wiper.