Divkid - Trace

Trace, a collaboration between Vostok Instruments and DivKid is an interpolating scanner – a smooth 4-channel crossfader capable of scanning between various sources.

Features:

• Four input channels
• DC-Coupled inputs for use with both audio and CV signals
• Custom response curve for the faders, designed to improve the response on middle positions
• CV-controlled scanning with onboard attenuation and inversion of the modulation signal
• Low noise analog VCA circuits

Trace is what you would call an “interpolating scanner”. It is based on a concept introduced by Jurgen Haible in 1994 and later enhanced by Donald Tillman in 1999. "Who they are?” – That’s a separate chapter altogether, for now let’s just say they are OG wizards of synthesizer history and each contributed in their own way - well worth reading up on in any case!

So back to the module - what is it? In essence, it’s a hybrid device that combines the functionalities of a signal selector and a crossfader. Taking a quick glance at the module pretty much sums up what it is about - you have 4 inputs and a slider in the middle of the device that lets you transition between each source.
A simple VCA Mixer obviously also lets you blend and mix several sources, but sometimes the individual control of each input might in itself be too much control. Sometimes an even more minimalist approach might be better suited for what you are after. Thank the heavens then for the invention of the interpolating mixer that lets you blend your sources with just one single control.

Trace comes with its own take on the original interpolating scanner circuit and features a fine-tuned slope response that makes sure to keep the transitions between the inputs as smooth as possible. It also improves its behavior when controlled by external CV signals.
Speaking of external CV signals - there’s a scan input that lets you control the “crossfader position” between the sources. It also features an attenuator that lets you turn down signals that might be “too hot” to work within the scanning range. Any signal that goes beyond that range just locks in on the last input in either direction - this might come in handy if you’re after an asymmetrical scan. There's also a polarity switch that can invert the incoming CV scan signal.
Both the inputs and the outputs are DC-coupled which means that Trace is able to work on both audio and CV-signals. 

This is a cool little utility module that lets you do anything from waveform morphing, CV-controlled transitions to audio rate scanning. It is a nifty little navigator of timbres and more, and at only 4HP this might just be the slimmest interpolating scanner around. An interesting take on a classic circuit remade for Eurorack!