Neutral Labs Scrat: Steiner-Parker filter with hackable resonance

05 Jul 2022 by Robin Vincent | Approximate reading time: 2 Minutes

Neutral Labs Scrat · Source: Neutral Labs

Neutral Labs Scrat cartridges · Source: Neutral Labs

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Scrat features some patch wire points on the front for swapping out diodes, resistors and capacitors. It lets you hack into the resonance circuit and cause all sorts of trouble.

Scrat

The Steiner-Parker filter is already nicely aggressive and Neutral labs is very good at getting a nice bit of bite out of things. It’s a 2-pole, 12dB/Octave filter with both high and lowpass modes. Before the filter, you’ll find a drive circuit for piling on the anger. There’s CV control over the resonance and cutoff that also has attenuation. A couple of switches are on hand to change the behaviour of the resonance. One starts with smooth and clean and then switches it to nasty. Once locked into the nasty position you can favour the high or low harmonics via another switch. And this is all without any weird circuit hacking.

Once you start messing with the circuit, all sorts of other things can happen. There are two rows of 5 patch points; both rows work the same way and can be used simultaneously. The two outside points are set in parallel to the main resonance feedback circuit. The two inner points are in series and the middle point is to ground. Plugging in various resistors, capacitors (non-electrolytic) and diodes will have different effects on the character and behaviour of the resonance. The key is to experiment! Behind the scenes, it’s all protected with 100ohm resistors so there’s no danger of doing any damage to anything.

Cartridges

Neutral Labs has come up with some very cool “preset cartridges”. These contain a few components put together into a little SD card-like cartridge that you plug straight into a row of patch points. There seem to be four of them and they’re named after various nuts. I believe Neutral is offering them as an optional extra, although they should probably just come in the box.

Neutral Labs Scrat cartridges

Scrat should be available in July from the usual places you can buy full module kits. Apparently, it’s a simple kit with no surface mount or tricky parts. Sounds like a great way to add an interesting and tweakable filter to your setup. The price is yet to be announced.