Positif Synth School

Befaco Sampling Modulator Review

So, what does the “Sampling Modulator” do?

Like most of Befaco’s lineup the Sampling Modulator follows the west coast synth design philosophy of “one module: many functions”. It can be used as a gate sequencer, clocked sample and hold, oscillator, clock generator, sampling shaper and even as a bit-crusher of sorts. All in all, this makes it an extremely versatile module, and considering that is only 8hp in size -like most “regular” Doepfer modules-, the bang for buck/hp is quite high!

Today I have the pleasure of reviewing Befaco’s Sampling Modulator eurorack synth module. Befaco is a spanish synth manufacturer whose output is focused mainly on Eurorack modulars.

They started as a small DIY project community, hosting workshops at Barcelona’s “Hangar” art production center. I used to be one of those attending these workshops, and with their help and knowledge built a few of their modules – as my “x0xb0x” tb-303 clone and my “Elkorus” solina rack chorus unit-. Not only they’re great synth designers, they’re also very nice chaps and will do whatever it takes to help you finish your DIY project.

Befaco’s modules were build to a custom format at first. They used eurorack 3u size panels, +/-15v power -much like 5u modulars- and banana connectors -like Buchla and Serge systems-. Today they have adapted their designs to the eurorack “standard” with +/-12v rails and minijack connectors, but you can still build their modules with your choice of connector -current PCBs are designed to fit both options- and even power -some modules work equally well at both voltages-. The modules also look much better now in my opinion, since they have abandoned their self drilled white DIY panels in favour of a professionally silkscreened black design -that reminds me of big “macho” modulars-, with much better interface layouts as well.

The Looks:

The module is finished in glossy black, and the panel is a sturdy metal frame. All the pots have metal shafts, which is a nice choice for durability -some manufacturers cut corners on this-, and everything is hand soldered using through hole components, another win on my book -easier servicing should anything fail-. Also, both PCBs are set parallel to the front panel so the module is quite “skiff friendly” as you can see in the pics.

The switches have red colored caps -a nice touch- and the interface doesn’t feel cluttered by eurorack standards -the upper switches might be a bit too close to the knobs, but that is no worse than most euro modules this size-. Last but not least, the panel has wider than normal screw holes drilled in, so it will be easier to fit in most cases when you mix modules from Analogue Systems and Doepfer for example, which use different hole spacing.

Sound and function:

In Frank Zappa’s own words “writing about music is like dancing about architecture”, and I think that describing the sounds and patches achievable with this module is quite a daunting task itself. That’s why I’ve made sound demos to better showcase most of it’s functions.

First here’s a patch focusing on the gate sequencer feature. For  this demo I’ve used a MusicThing Turing machine random sequencer and a typical “vanilla” synth patch -two VCOs into one 24dB lowpass filter into one VCA, while these last two are controlled with two ADSRs-. The Turing Machine is providing the “notes” -CV- while a quantizer turns the random madness in to something “musical”. My turing machine can also provide gates if needed, but I’ve chosen to use the Sampling Modulator instead.

It’s a very nice combo indeed: Firstly, the Sampling Modulator has a clock generator, which the turing machine lacks, and with the individual switches you can have more control over which steps are active or not while maintaining the note randomness. Each step has “on” and “off” positions as well as a “reset” mode. When one step is “resetted” the sequencer changes length, but the clock keeps working, so if you put one step in “reset” mode momentarily and then revert back to “on” or “off” status, the order of the gates changes it’s relation to the steps of the other sequencer -the Turing Machine in this case- since the other sequencer was still being clocked by the Modulators clock out. This is very useful to get numerous variations out of one single melodic sequence as you can hear in the demo below.

Next is a demo showcasing the module’s bitcrushing abilities. We’ve used a doepfer a-110 VCO set to a square wave as the source. As you manipulate the controls you can get more harmonics and artifacts out of a simple sound source like a sine or triangle wave, plus it adds an 8bit edge to rich harmonic sources like square waves. This could also prove useful with complex sound sources like music.

The module can also be used as a square wave VCO via the trigger out. Here we have used it with a doepfer a-107 as the filter. If you manipulate the switches it’s also possible to get different waveforms out of the module not available on traditional VCOs.

The interesting part comes when using it for cross modulation on other VCOs. If you turn one of the switches to the “off” position, the complex outputted waveform creates unusual artifacts while it modulates the VCOs CV in, and we found a cool bonus use for this: hihats!

Add to this the fact that you can also use it as a clocked sample and hold, that will be in time with your other sequencers or your DAW -via a Kenton Pro Solo for example- and you can see that it’s indeed an interesting addition to any euro setup.


The sampling modulator is pretty much a “swiss army knife” module, much like the manufacturer claims. It’s very versatile, but we’re not talking about versatility in an “utility module” kind of way, it’s more like a compendium of weird, unusual features, unlike other multifunction modules like Maths. It does many things but most of these features have a certain “twist” that makes them unique.

It’s a welcome addition to any synthesist or sound designers’ arsenal and works awesomely as a companion module for MusicThings Turing Machine or other similar sequencers. At roughly 108 euros -if you buy it as a DIY kit on Thonk-, it certainly is a lot of module for the money, and if you don’t feel like soldering is your thing you can also order it already assembled for 210 euro. For more info click here!

All in all, a great module. Congrats to the people at Befaco!