Knobs on the end

Revised and updated 30 Mar 2019.

It took me only about 45 minutes to put together the GMSN! Pure VCA. The part count’s pretty low. Most of the functionality is in the THAT 2180 amplifier IC. Everything seems to work well. As it says on the box, it’s a pure VCA, no obscure weird features, signal in CV in signal out two knobs, boom.

This is the second Eurorack module I’ve bought as a panel and PCB set, sourcing my own parts. But it’s the first time I’ve come up against having to make decisions about the module’s visual appearance. With a full kit (or assembled module) you’re pretty much stuck with whatever the designer’s aesthetic is. But get a board and panel and guess what: The panel’s the panel, but you’re in charge of selecting the knobs. Well, the Buffmult has no knobs, but that’s the exception.

I happen to really like the classic Moog look, black or dark color panel with white lettering and black fluted knobs with aluminum inserts and white pointers. None of my modules so far look like that, though. The Żłob has an ornate red-on-black panel design with “knobs” that are really just the black potentiometer shafts with white pointers. The horstronic. has an uncolored aluminum panel with no knobs. The Befaco comes closest with a dark blue panel and white lettering, and a big fat fluted knob for the octave selector, but it’s white, with a black line for a pointer. The tuning knob is white, too, though it’s small and round with a black dot pointer, while the PW knob is small and red with white line pointer. There are similar but not quite matching small red knobs on the AI Synthesis modules, with red toggle, red button, and a larger red knob in a different style on the ADSR, and uncolored aluminum panels.

I considered getting a match (more or less) for those small red knobs to use on the VCA. But then I figured, I guess if you’re going to have a patchwork of modules from different makers, you might as well lean into the diverse look. Nearly-uniform knobs on not-at-all-uniform panels doesn’t make that much sense.

But nor, I think, does austere vintage black and aluminum next to bold red. Especially not on the Pure VCA panel, which has a rather informal look to it, with a slanting display typeface, and swooshy arrows around the pots which are intended, I guess, to help those who have trouble remembering how knobs work. Moog style knobs on that panel would be kind of like a tuxedo on a sheep.

Yeah, the mounting hole convention differs from the other modules, and no, I’m not using slide nuts. Someday maybe I’ll open up the holes to ovals. Someday.

I played around with drawing circles on top of a picture of the VCA front panel and decided something in the 13 to 15 or maybe 16 mm diameter range would be best, and there are photos on the Tayda site of the various knobs, but it’s hard to really get a sense of what looks like what without examples in hand. So I ordered seven knobs, in a few different sizes and colors, to evaluate for this and for future modules.

These are the KN1360 ABS fluted blue knobs, 16X12 mm. Obviously resembling classic Moog knobs, but blue. Now it’s a blue tuxedo on a sheep, which is a whole different thing.

But an obvious problem is the size. The diameter is large enough to partly obscure the swooshy arrows. And you may or may not have noticed, but the upper arrow is a little misaligned, not quite centered on the hole. With knobs this size the misalignment is made more obvious because the graphic is so close to the outer edge of the knob and fails to follow it.

The KN1250 ABS fluted blue knobs 15X11 mm are a little smaller. Similar shape, but no insert.

They don’t obscure the arrows, but they’re still large enough to call attention to the graphic misalignment.

Here is the KN8F blue knob 16X15 mm.

This is also large enough to obscure the arrows. All three of the knobs so far have been described as “blue”, but this is a very different shade of blue, darker and more serious. It also has a visual style that… sort of puzzles me. There’s a lot going on. There’s the, I don’t know the standard term, grooved texture of the sides of the knob, but also a bit of a wider skirt at the bottom, with a notch in the skirt lining up with a slot across the full width of the top, with the pointer a small dot in one end of that notch… very busy. That slot particularly bothers me. What’s the point of it? I don’t know. Anyway, I’m not enthusiastic about either the color or the design.

Last we have the Knob Davies 1900H clone in both blue and violet.


It’s blue, Jim, but not as we know it. A lighter shade this time, and to my eye a bit wishy-washy. The violet’s more assertive. There aren’t many violet or purple knobs on the market, probably for a good reason. Then again, why not? Wikipedia says “According to surveys in Europe and the United States, violet is the color people most often associate with extravagance and individualism, the unconventional, the artificial, and ambiguity” and if that’s not right in line with modular synthesis, I don’t know what is. Aside from the color these are pretty near identical to the small red knobs on the AI Synthesis and Befaco modules, and while to me uniformity of knob color is a dumb thing to try for, (partial) uniformity of knob style might be a good idea. Anyway, these are smaller in diameter and call less attention to the graphic misalignment. If the swooshy arrows were gone I’d prefer larger knobs, but as it is, these are what I’ll use. In violet. I only got one in that last order, but I have more coming.

The other good thing about knobs is you don’t solder them on. Undo the set screws and you can yank them off and toss them out, if you change your mind. We shall see.

Edit to add: Here it is, with knobs.

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