Description

Slimline DC Blocker

4× DC offset filter (AC coupler) for Eurorack in 2HP

Reliably remove DC components (DC offset) from audio, sub-audio and CV signals – and bring order to patch chains that would otherwise be thrown off by invisible offsets. The Slimline DC Blocker preserves the musical core of your signals: it cleanly blocks DC, keeps the passband neutral (unity gain) and ensures downstream modules (mixers, VCAs, filters, compressors, waveshapers) behave stably and repeatably.

Especially with very slow modulations, or when saturation/distortion generates offsets along the way, the DC Blocker helps you reclaim headroom, reduce click/pop artefacts and make CV sums precise again. Thanks to its active Butterworth topology, the passband stays flat and unobtrusive, while buffered outputs with low output impedance can drive even long patch chains cleanly – ideal in the studio as well as on stage.

Why a DC blocker?

• Fewer clicks & pumping in VCAs/compressors when offsets enter the chain
• More headroom: DC eats into the margin in mixers, VCAs and filters
• Clean summed CV & sub-audio signals without drift/offset errors

2HP compact – 4 channels for clean routing

Four paths for parallel processing, patch hygiene and clean signal flow across your system – despite an ultra-compact 2HP width. The Slimline DC Blocker gives you four independent channels so you don’t just fix offsets “somewhere”, but exactly where they arise or get in the way: before the mixer, after a waveshaper, in a summed CV bus or right before the recording path. That way you can stabilise multiple points in a patch at once, without constantly repatching or only “treating” a single problem source.

In dense Eurorack setups this is worth its weight in gold: you use a single space-saving slot and still get enough channels to keep audio, sub-audio and CV clean in parallel – for structured routings, repeatable results and fewer surprises at the next patch step.

Two response options: High Fidelity & Fast Settle

• 2× High Fidelity – fc ≈ 0.1 Hz: maximum signal integrity even at very low frequencies
• 2× Fast Settle – fc ≈ 1 Hz: shorter settling time, ideal when offsets need to disappear quickly (e.g. after saturation/FX)

Active Butterworth high-pass, unity gain

Unobtrusive in sound means, with the Slimline DC Blocker: DC removal happens precisely and under control, without your signal being “thinned out”, shifted in level, or having its behaviour bent by the load of the next module in the patch. Many typical passive RC filters may look simple on paper, but in practice they depend heavily on the connected inputs and cable capacitance – the cutoff frequency drifts, the settling behaviour changes, and depending on the patch you can get subtle (or quite noticeable) changes in bass/sub-audio, transients and the perceived “solidity” of the signal.

By contrast, the Slimline DC Blocker’s active Butterworth topology is designed to stay as flat as possible in the passband (unity gain) and to deliver a defined amplitude and phase response: you get clean AC coupling that sounds like “nothing” – except that unwanted offsets disappear. Especially with sensitive signals such as slow modulations, sub-audio-adjacent curves, or audio that has already been through saturation, wavefolding or complex sums, this pays off: less unexpected coloration, fewer patch-dependent side effects and overall more stable, repeatable behaviour – exactly what you expect from an always-on utility.

Buffered outputs, low output impedance

Driving downstream stages reliably means: you get a true active output driver instead of “just” passive RC decoupling. With typical passive RC filters, the effective filter behaviour depends heavily on what comes next – input impedances, capacitive loads from long patch cables, mults, the next mixer or VCA. This can lead to level loss, “soft” bass/sub-audio, unexpected time constants, shifted cutoff frequencies and, in the extreme, audible changes when repatching.

Instead, the Slimline DC Blocker works with buffered outputs and low output impedance: the filter stage is isolated from the load, so the behaviour feels consistent and predictable – even if you use long cables, feed multiple destinations or work in complex patch chains. The result is clean signal flow without unwanted “reading along” by the downstream circuit, less crosstalk and less risk that your DC-offset fix “moves” again at the next patch step. In short: you get DC removal that behaves like a robust utility – not a fragile compromise that reacts differently from patch to patch.

Typical applications

• Remove DC offset after wavefolder/distortion/saturation
• De-drift sub-audio/LFO before mixing
• Keep signal paths “clean” before recording/audio interface