Watch How 1993 Norwegian Distortotron Effect Processor Inspired Bastl Tromsø Eurorack Synth Module

Bastl Instruments have released a short film on the effect box from Norway made 23 years earlier, Distortotron. This analog downsampler & bitreducer helped Bastl create the Tromsø Eurorack module.  

Bastl Instruments in cooperation with Mental Overdrive made a short documentary about a unique piece of electronic music equipment from 1993 called Distortotron. They created this short film to trace the origins of the instrument and have even provided sound demos: 

Distortotron is an effects processor: downsampler, bitreducer and clipping overdrive. It was made in 1993 in Norway by Svein Berge and Henrik Sundt a.k.a. PSYBE for a Tromsø based musician Per Martinsen a.k.a. Mental Overdrive. The concept for such instrument came from the need to bring back the aliasing and noise of early 80s samplers and it heavily formed the sound of Mental Overdrive’s debut album Plugged released in 1995 which became the landmark of the so called Tromsø sound. The album got re‐relased in 2016 on Prins Thomas’ label Rett I Fletta.

The Distortotron inspired Václav Peloušek of Bastl Instruments to design a eurorack module called Tromsø.

Note: Svein Berge is NOT the guy from Röyksopp – he just shares the same name!

Distortotron back


The Distortotron has 3 sections:

  • Quante-sprang and Ditto stoei control “quantum noise” – or in better words quantized noise which emulates loss of bitdepth of the signal – therefore it is pseudo bitreducer. It probably forces the analog signal to become only certain set of fixed voltages and adds some noise similar to the low bitrate noise.
  • Taste-rate controls pitch of downsampling – analog sample and hold circuit with oscillator to reduce the sample rate of the signal and introduces aliasing.
  • Avklippings terskel and Ditto stryke control the clipping circuit  with adjustable thresholds and amount of clipping.
  • and output volume called NIVEAU (outdated Danish word)
Distortotron 1.0


More information about Distortotron: http://www.bastl‐

Mental Overdrive album Plugged from 1995 is reissued on Rett I Fletta label Reissue info:‐revisited/

Album on bandcamp:‐bonus‐edition‐album

Eurorack module Tromsø available from Bastl Instruments:  http://www.bastl‐


Rounik is the Executive Editor for Ask.Audio & macProVideo. He's built a crack team of professional musicians and writers to create one of the most visited online resources for news, review, tutorials and interviews for modern musician and producer. As an Apple Certified Trainer for Logic Pro Rounik has taught teachers, professional... Read More


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