jepyang

jepyang, 3 months ago

I haven’t bothered explaining what all this module does, since it’s basically a clone of another module

But now that it’s done I may as well give a quick rundown

The biggest “downgrade” from the original module is that the layout doesn’t make as much sense, going from three columns of jacks to five. Cold Mac had related functions in line with one another; Mac Salad is…a bit more loosey-goosey.

jepyang, 3 months ago

First off, some labeling conventions…

Inputs have a white line and are grouped to the left. If there is a signal normalized to the input, it is listed next to the jack with a dotted line.

Outputs have a silver line and a silver arrow and are grouped to the right

Seven jacks have a little flower growing on them. The six inputs with the flower, in addition to their regular function, form a mixer routed to the output jack with a flower, “Da Kine” (more on this later).

jepyang, 3 months ago

Now the controls…

There is a big knob and an input jack labeled “Scoop”. The signal at the jack (bipolar signals are fine) is summed with the knob’s offset (+/-5V). The result (I’ll just call it Scoop from here on out) is used internally in several locations, either as a normalled connection or a control signal.

jepyang, 3 months ago

Next is the panner/fader.

This section has four inputs: right, left, fade, and offset. Right and left are normalled to +5V and -5V respectively. Fade is normalled to Scoop. There is also a knob for attenuating the signal at Fade.

It’s got two outputs: right and left.

Essentially, it’s two crossfaders that work in opposition to one another… (contd)

jepyang, 3 months ago

So with Fade at -5V, you get 100% of the left input and 0% right at the left output, and 100% right, 0% left at the right output.

As you increase the voltage into Fade, each output fades from one input to the other. So at 0V, you should get equal parts left and right inputs at both the left and right outputs. And at +5V, you get 100% of right in the left output, and vice versa.

So using 2 inputs and 1 output is a crossfader; 1 input and 2 outputs is a panner; or 1 input and 1 output is a VCA!

jepyang, 3 months ago

The fourth input is Offset, it simply sends some signal to both inputs.

There is also a trimmer around back for adding offset to the Fade control. This is usually gonna be at or near zero, but it’s an adjust-to-taste situation.

jepyang, 3 months ago

One last note on the fader section… It’s made of four vactrol-based VCAs. So the response is a little weird and nonlinear, and they don’t turn off as fast as they turn on.

It’s not a bug, it’s a feature!

They definitely aren’t mathematically ideal VCAs. But they have some character! They work mostly like how you expect them to, but when they don’t, they usually do it in a musically interesting way.

There are a bunch of trimmers to help match all the VCA levels.

jepyang, 3 months ago

Next section: analog logic! We have an OR circuit and an AND circuit, both w/ two inputs, one output.

Analog logic can be weird if you’re used to digital logic, but it’s exactly the same. For OR, if either one input or the other is high, the output is high. The only difference here is that you can use analog input to get analog output. Whichever OR input has higher voltage at any given moment is the signal you’ll see at the output.

jepyang, 3 months ago

AND works similarly, except that it always outputs whichever signal has lower voltage at any given moment.

You can maybe see how the two outputs here would be complementary. As such, the first AND input is normalled to the first OR input, and both second inputs are normalled to Scoop. With a signal going into OR(1), OR out will always show any part of the signal above Scoop, and AND out will show whatever portion of the signal falls below Scoop.

jepyang, 3 months ago

Rectify is a simple one. One input, one output. It’s a full wave rectifier!

Basically, whatever goes in, you get the absolute value out. Any part of the signal that falls below 0V gets flipped positive.

Something fun: if you put in a saw wave, you get a glitchy triangle wave out. If you put in a triangle wave, you get another triangle wave at double the frequency out.

jepyang, 3 months ago

Follow is an envelope follower based on the one in the ARP2600. It has no input of its own—it takes its input from the Rectify input jack.

Basically if you feed it audio, it generates an envelope/control voltage according to the volume of the input.

So feed it, for instance, a kick drum. Every hit of the drum would generate a little envelope at the Follow jack, which could open a filter. Or you could invert the output and send it to a VCA and you have a basic sidechain compressor effect!

jepyang, 3 months ago

Puka is a weird one. It’s a sort-of wavefolder…

Basically, anytime the input is positive, Puka adds a -5V offset to the output; and when the input is negative, a +5V offset is added. The result is a 10V discontinuity at every zero-crossing.

It’s kinda hard to grok without looking at the result. But if you send a sweep from -5V to +5V, the output starts at 0V, will climb to +5V until the input hits 0V…at which point the output swings instantaneously from +5 to -5V, then climbs again till 0V.

jepyang, 3 months ago

Then we have Holoholo (which means “wander aimlessly”). This is the most idiosyncratic circuit in the module—I’m not aware of any other eurorack module besides the original Cold Mac that includes anything similar. (I think there’s some Buchla or maybe Serge modules that have something similar?)

One output, takes input at the Puka jack.

This is actually an analog computing circuit. The output is the integral of the input…if calculus is your thing.

jepyang, 3 months ago

If calc isn’t your thing…

Basically anytime the input is positive, the output will climb; and when the input is negative, the output will fall. The amplitude of the input, either positive or negative, determines the rate at which the output moves.

So if the input is 1V, the out will sloooowly drift up, no matter its current value. If the input goes to 5V, the out will drift up much faster. And if the input goes to 0V, the out remains at its current level.

jepyang, 3 months ago

Everything else in Mac Salad can technically be replicated with other modules. Even Puka, which I don’t think I’ve ever seen as a complete circuit in another module, can be put together with a comparator, an inverter, and a mixer. It’s more about how it’s all pre-connected that makes it so useful.

But Holoholo… you can’t really build it from other blocks! As a function, it can’t really be broken down into simpler bits. It’s, uh, not super useful, but it is really neat.

jepyang, 3 months ago

@darlingofinana 👎 “I’m red/green colorblind”

👍 “I’m queering the red/green binary”

jepyang, 3 months ago

Hey just want to send out thanks. Some people bought some music today, enough to make a good dent in the car repairs. And a bunch of people listened to the music today too, and that feels really good. And thanks to everyone who boosted as well.

💜💜💜 the fediverse rules, I love all of you

jepyang, 3 months ago

@vapaad Not a teacher but my mom taught elementary school my whole life and I know this was a perennially popular sentiment:

jepyang, 3 months ago

@ifixcoinops Reminds me of when I tried to figure out how to get dithered graphics in 256 colors in Unity and it’s like “ok here’s a shader to overlay on your camera’s field of view, hope you have a decent graphics card though”

like holy shit when did it become computationally prohibitive to do shit that worked fine on computers less powerful than what’s in my toaster?

jepyang, 4 months ago

@gsuberland This is weirdly affirming, as someone who has basically no idea what I’m doing.

jepyang, 4 months ago

@JessTheUnstill @cstross @NunavutBirder @graydon The United States?