Let's start with something blissfully simple. The 4R module from Transient can generate four random values from a single trigger in a very neat 2HP module. There's a second trigger input that splits the 4R into two independent generators with two different outputs. The outputs are held until the next trigger, which gives classic Sample & Hold behavior.

The module can produce unipolar or bipolar outputs, selectable via jumpers on its PCB.

It's really no more complicated than that; all you need is some triggers and you'll get four uncorrelated random voltages that share identical timing. That is pretty awesome, especially given the low HP count. If you're looking to fill in a 2hp space in your system, this is one of the first modules Perfect Circuit would recommend.

Perhaps as a reaction to overly complicated random generators, Ben "Divkid" Wilson and Steady State Fate came up with probably the most straightforward Sample & Hold generator you've ever seen. RND Step can generate three random values from a single trigger or split down into three independent Sample & Hold circuits running of their own triggers. Each channel has a pair of built-in noise sources, so you don't have to feed it something externally. And you get both a unipolar and bipolar output.

You can bypass the internal noise source by patching something into the Sample input. This could be another noise source, but it also opens RND Step up to the possibility of grabbing intentional voltages from elsewhere. For instance, you could use it to sample and hold a single note from a sequencer, transform an LFO into a stepped arpeggiation, or even bit-crush the heck out of some audio.

RND Step has bags of quality, lots of randomness from very little work and room for creative possibilities, all in a compact 4HP module.

One of the byproducts of our search for randomness is the generation of noise. We often see it just as something we're sampling to obtain a value, but noise is also interesting in itself, and so you'll often find noise outputs on Random Voltage Generators. Flurry is all about the noise and in fact, has 16 digitally generated algorithms to produce just that. These include vinyl crackles, water drops, FM sweeps, radio static, hum, particles, cymbal clangs and other such chaos and nonsense. Flurry also has regular flavored white and pink noise, which is normalled to the sample input when nothing else is patched.

The noise outputs can be used in all sorts of creative ways throughout your rack. Each algorithm has a couple of parameters you can control, and you can also morph through each of them and modulate that movement to form a whole world of chaotic texture.

Rather than relying on external triggers, Flurry has an internal clock running a pulse that can dictate the rate of change. It also has a Slew control, which slows down the leap from value to value and introduces a glide to give a smoother output than a stepped one.

Ultimately, you use the any of the noise algorithms or external sources to feed the sampling input from which you can derive a random value. But Flurry is spewing possibilities from all sorts of outputs, making it a very exciting module.

If you'd like things a little bit more complex, then spend some time riding the random wonders of tágh. It has a regular analog sample and hold circuit accompanied by a white noise generator, but it also has a digital random voltage generator, a weird LFO and a probabilistic trigger generator. It sounds like the sort of thing that's going to enjoy playing all by itself.

Beyond the regular S&H, Tágh is running six experiments in randomization. From classic stepped to looped stepped, LFO with downsampling, LFO linked to probability and a great deal of chaos. The slider in the middle of the module changes a specific parameter for each algorithm. It's also tied to the clock and messes with the probability of the module maintaining its timing. You can control the internal clock with a tap-tempo button, which can also be used to grab a value on a single tap.

As with the Flurry, you have several outputs operating independently of each other, giving you space to generate melodies while modulating waveshape, filters or firing envelopes. Tágh is a little powerhouse of possibilities.

Being Ultra-Random suggests that some random is more random than others, which all seems a bit implausible, but we're going with it. The emphasis is to stick with the Sample & hold and squeeze as much juice out of that as possible. Ultra-Random Redux sets up two sample and hold circuits feeding off an internal noise generator. You can take either output on its own but also, and this might be where the Ultra comes in, you can take a toggled output that switches between the two outputs in line with the clock.

Another section of the module deals with a random pulse generator. This can be a completely free-flowing river of blips, or you can quantize it to the clock to find rhythms and patterns. The nature of the output is reigned in with a Density control while the Divisor knob plays with the resolution of the rhythms.

Meanwhile, a slew circuit can be used to smooth out the edges of the pulse or random output. It gives you a whole other output filled with ever-changing values of voltage and probability. URR gives you a lot to play with.

The VCV Random is the hardware projection of a software module. What I mean is that it started life as a module in the VCV Rack Eurorack simulation, and Nano Modules have made it into real live module for our racks. It uses some really simple ideas to produce a nuanced and controllable level of randomness in a very intentional module.

What's great here is how easy it is to control and how you feel that you are directing the results far more than any other module in this article. The output is based on a mixture of four factors: Rate, Probability, Randomness, and Shape, which are controlled by the sliders on the front or via CV. Simply shift the rate slider to increase the internal clock and the generation of new values. Push the probability to suggest how likely a new value will appear on the next tick. Randomness dictates how far from the original the next value can travel. And then, Shape adjusts the slide to the next value from stepped to smooth.

The result is a very manipulable stream of randomness that can spin from chaos into closely controlled rumblings. The four outputs, stepped, smooth, linear, and exponential, give you playful variations that are just different enough to give texture and character to your modulations. It's the most predictable of unpredictable modules.

The noise is simple enough, providing three "colors" of audio noise. The fluctuating random voltages are simple, smooth-moving modulators that emit a constant flow of ever-changing voltage. The knob and CV input controls the rate of change, and both channels are completely independent. For quantized random voltages, the flowing signal is reduced to steps through the quantization knob and then distributed via two different mathematical equations. The 2 to-the-power-of n output spreads the possibilities across the full 10 volts. The n+1 output provides fewer overall options, for applications where a small number of potential "random" outcomes are desired. The stored random voltages throw out a range of stepped values that are guided by the probable of change—with one output dedicated to full-range random voltage generation.

The Sample and Hold section is fairly straightforward, with a sample input, trigger input, and CV output. You have some alternative outputs based on derivations of the incoming pulse—essentially combining a two-step trigger "counter" with two additional sample & holds for outputs that only update with every other incoming pulse.

Lastly, the Integrator section is essentially a slew control that will smooth out stepped voltages and is perfect for working with the stepped outputs of other sections.

You have three sections: Random Audio, Random CV and Random Clocks. The audio section is essentially a chaotic sound generator generator that creates general sonic debauchery through texture-inducing ring modulation of a pair of VCOs. It also includes a separate output for each, giving you multiple waveshapes which you can use for other things.

Meanwhile, in the middle, you have a random voltage generator with stepped, smooth and "Woggle" output. The Woggle is similar to the smooth in that it slews the output, but it does it differently and more weirdly. The bottom section deals with the clock and generation of gates. You can control the speed and even advance the clock manually while deciding how often the Burst output gets to do its thing.

While it's not a 266, the WoggleBug offers something quite unique in terms of modulation and possibility.