Hacker Remix

Eurorack Knob Idea

290 points by po 1 day ago | 108 comments

bondarchuk 1 day ago

>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.

enneff 17 hours ago

This is why I really like Intellijel’s designs. They generally have attenuators on the inputs for which it makes sense, and those attenuators are the small stick knobs. While they use larger knobs for more central module functions.

Eg: https://intellijel.com/downloads/manuals/rubicon_manual.pdf

kennywinker 22 hours ago

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.

robotresearcher 21 hours ago

The attenuator-inverter is super handy too. A gain knob that goes from -1 to +1 X.

BlandDuck 21 hours ago

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.

nine_k 17 hours ago

The benefit is saving space. Imagine a 10x10 grid of such jack / knob inputs.

malthaus 20 hours ago

the smartest pattern is used in mutable instruments beads, the "attenurandomizers"

it packs a ridiculous amount of functionality into a single plug & knob combo

dimal 20 hours ago

I like it, but the best modules already have knobs and jacks for everything. When you have CV going into the jack, the knob acts as an attenuator or attenuverter. This means that the modules are generally larger. Make Noise generally does this and their modules are consistently bigger than everyone else, and they're also some of the most popular. Look at Maths. It's a slope generator and a mixer. It's fucking huge. But everyone has it because it's patch programmable. The problem in Eurorack is instead of making things patch programmable, they try to fit in a ton of functionality into a small space, so you have a lot of modules that have multiple modes where buttons and knobs all have different meanings depending on what "page" you're on. Fuck that. Almost every time I try a module like that, I end up selling it.

He's right about the interface being the point of Eurorack. Plugging things into other things is the whole point. When I have a module that has hidden state, I forget what state it's in or what the knobs mean. I end up avoiding those modules. With cables and knobs, I can see the state of the whole system. I need good cable management to make sure it's not spaghetti, but I already do that in code already, and it's not that different.

joemi 23 hours ago

It's an interesting idea (truly a clever way to accomplish this!), but I think it's addressing the symptom, not the problem. The symptom is that some jacks don't have associated knobs. The problem is that either the module designer or the module user is overly obsessed with miniaturization. The designer is at fault if it's a parameter that really should have had a knob with the jack and they avoided including one in order to keep things small. The user is at fault if they're trying to stay so space-constrained that they can't fit a module that outputs an DC voltage set by a knob into their case. There are numerous modules that do this (and often that attenuvert as well) and many of them are fairly small too.

anigbrowl 13 hours ago

The problem is that different people have genuinely different ideas on what kind of modulations are sensible. My go-to example on this is E-mu gear - a company that started out making big modulars in the 70s and went on to dominate the sampler/rompler space for about a decade before going bust during the dot com boom and being absorbed by Creative.

the nice thing about E-my synths was that they nearly all had big modulation matrices included, although users were often defeated by the 2-line LCD on their romplers. But one strange omission from the modulation destinations was filter resonance; all their later modules included a huge (arguably excessive) selection of filter types, but for reasons of computational efficiency you could not adjust the resonance while a note was playing. This wasn't too bad from the front panel because most people want to ride the cutoff rather than the Q, but the inability to modulate it inadvertently highlighted some limitations of the filter design.

I can see both sides, as I am a 'let me modulate everything' person when choosing gear but at the same time I quite admire 'opinionated' synth designs where flexibility is traded off against maximizing sweet spots. Sometimes it's better to have an instrument with limited sonic range but which responds very consistently within that, so 'you can't get a bad sound out of it'.

adrianmonk 10 hours ago

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.)

raphman 5 hours ago

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.