Behringer 121 Dual VCF

The 121 Dual VCF is an interesting module, which I would rate as a Behringer product rather than a clone. The LP filter sound is smooth and pleasant, never harsh. The resonance has a nice timbre until it gets into self-resonance. The module offers an HP filter as well with 3 different selectable cut-out levels. The 3 way mixer is the winner feature here as it allows you to mix different audio signals within the module, each IN has an attenuator. Sliders a re smooth and precise. The only hing I find awkward is the size of the knobs which are very small and once the unit is patched it is very hard to reach them but for the price vs performance I would just take it as it is.

If you're looking to bring a classic filter to life in your modern eurorack setup at minimal price, Behringer provides the way. Arguably as high quality or better than any offerings from Roland themselves, who have frankly ignored the Eurorack market at their own loss. Behringer is committed to reviving the classic Roland and Moog modular synthesizers of the 70s and making high quality, modern, careful recreations of all of their models and more.

Getting your hands on a real 121 Roland module in working condition from the 70s, provided you even have the right place to rack it safely, will cost you upwards of $1000 and not be different in any noticeable way except perhaps that single unit's own wear from 50 years of being on this earth.

Roland's own revival would be their, confusingly renamed "SYS-521" Eurorack module and frankly, the look and feel is less like the original, and it costs 5x as much as this Behringer unit. Save yourself the money - if this is the filter you want, go Behringer..

Very clean sounding jup8 style filter, times two. The only real negative is that the input levels are low biased, it takes effort to overdrive this thing, and consequently for this filter topology in general if you increase resonance the output level tends to lower significantly. That said, I love it, 3 sig inputs with attenuation, 3 control inputs with attenuation. 2 outputs. Yesss! Long time ago I found a system 100 samplepack and mesmerized by the sweet, pristine, deep and liquid cutting nature of this filter. So yeah this thing does not dissappoint, even if it contained one filter its worth the money, but hey you get two. Selfoscillation occurs kind of abruptly but I don't mind. The selfoscilation is always very controlled and sweet. The whole ergonomics is very natural, compact and to the point, as in a total joy to use. As it's all surface mounted so modding seems unappealing although I might get into bypassing some input resistors to crank up the gain.

This VCF features 3x2 3.5mm inputs with attenuators and 3x2 modulation inputs with attenuators. It has 2x2 Outputs and a HPF with 3 modes (a la juno).
Yes the knobs are small and somwhat hard to reach when it is patched in, the sliders are small to but easier to reach and they all feel sturdy.
The sound quality of the filter is good, it has self oscillating capabilities. It has a rather fast and hard response, good for pinging and such. Over all it is a very good module given all you get. 2 separate filters with 3 modulation inputs each. The only downside is that it's hard to tweak and reach in between cables. But I can live with that.