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Stereo EQ & VCA Compressor By Rory Dow
Published February 2023


Billed as an instant mastering device for on‑stage use, the DOCtron IMC (Instant Mastering Chain) could well be an entirely new class of audio processor.

The DOCtron IMC is a collaboration between German manufacturers DOCtron and electronic musician and YouTuber Martin Stimming. Essentially, it’s a high‑quality stereo mastering chain in a portable package — it measures 15 x 15 x 6cm. The reason it’s so compact is that it’s designed primarily for live musicians (although it will work just as well in the studio). Imagine you are performing live with electronic equipment; maybe some modular, a drum machine and a synth or two. Your set follows directly after a DJ who has been playing finished, mastered material. Your setup is unlikely to have the loudness to compete. Adding that ‘mastering sheen’ to a live performance can be difficult. Do you choose a laptop running plug‑ins, which adds latency and unnecessary complexity? Or do you go for rack equipment — compressors, EQ, limiters, and so on — which are bulky, heavy and require multiple power sources? The IMC (Instant Mastering Chain) aims to solve this problem.

You’ll probably already have noticed that the diminutive size of the box doesn’t translate to the price. That’s because this box is full of no‑compromise electronics, including Lundahl transformers, DOA op‑amps and THAT VCAs. All of which help to make it sound fantastic: the ‘mastering’ part of its name is not a lazy marketing description.

Watch our SOS video chatting to Martin Stimming about the DOCtron IMC at Superbooth 2022.


The IMC weighs less than a kilogram and is supplied in a tough ‘road‑proof’ carbon case. The power supply is separate, which I know some dislike, but it’s perfectly understandable for a small box like this, and it comes with a soft carry case that should prevent it from getting scratched in transit.

Audio comes in and out via pairs of balanced quarter‑inch input and output jacks (apparently, some early units were unbalanced). The EQ comes first in the signal chain and offers low and high shelves. The circuitry is based on a Trident EQ design and does an exceptional job of teasing out the sub and adding air. Each of the shelves can add or remove up to 14dB of gain, which is far more than you might expect from a mastering chain but can be great when using the IMC in the studio. The EQ can be bypassed using one of the three illuminated buttons on the front panel, which is handy for quick comparisons....

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