IM1 M/S Insert Master

Insert Master featuring Mid/Side Conversion & Stereo Base Control

IM1 M/S Insert Master


Another AM1 Spin-Off

AM1 – our state-of-the-art pure analog mixing console – does not only stand for superb sound quality but also for elaborate functionality. The essence of AM1 Insert- and Stereo-stages has been extracted and then supplemented to form a unique stand-alone unit. IM1 has been designed for setting up a high end analog signal chain in conjunction with other analog equipment.

IM1 development


The main features explained in this short video

Special Features

All you can expect from an insert

Dedicated level BOOST, DRY/WET Ratio control, MID/SIDE stereo conversion, individual I/O MONITORING.

Impedance Select switch (Z) on Insert Return.

IM1 Insert
IM1 stereo base

Stereo Base Control

Classical circuitry based on MID/SIDE stereo technique, adapted to real-world applications


Compatibility to standard 500 frames (1-slot breakout panel providing stereo insert I/Os included). Special rear panel covering all connectors when operated in Zähl Rack.

IM1 Manual Download PDF

"I've waited nearly a year for this! The Zaehl IM1 is taken from the very heart of their magnificent AM1 console. It has stereo base control with constant mid option, a return for mid/side processing with wet/dry, meaning I can put any one of my hardware units as an insert with wet/dry/mid/side function, plus manipulate the image with the stereo base control! I am in audio nerd heaven. It looks like such a simple box, but under the hood is endless creativity. Very happy right now!"

Torgeir Byrknes aka TeeBee

Toorgeir Byrknes aka TeeBee

Details IM1

Design Features

  • stereo design for mix & mastering as well as voices & instruments
  • highly musical design
  • intuitive, user-friendly, self-explaining layout
  • lowest noise and distortion signal paths built with highest quality components
  • no microprocessor, no clock pulses, sequential logic only
  • individual power stabilization on each module, no switched power circuitry
  • number of I/Os exceeds API 500 standard, connector extension included:
    - upgrade to special rear panel for Zähl Rack 500 series with additional XLR Insert I/Os or
    - additional 1 slot front panel with 4 XLR Insert I/Os as adaption to standard 500 series rack
  • all other specs compatible with API 500 series specs, basic unit occupying two slots

Input Stage

Input Stage
  • electronically balanced, max. level > +26dBu
  • INPUT GAIN range +/- 10dB, L/R BALANCE range +/- 2,5dB
  • GAIN and BALANCE with trimmed zero position
  • SIGNAL LED (green) level present, individual Left/Right
  • O/L LED (red) overload warning, individual Left/Right


  • SEND BOOST control with up to 20dB gain at INSERT send
  • RETURN RATIO crossfader for DRY/WET mixing at INSERT return for parallel compressing, EQing etc.
  • Z-Switch - impedance selection for Insert Returns. Optimum sound results by impedance matching, e.g. when inserting vintage equipment.
  • switchable MID/SIDE STEREO conversion on INSERT SEND/RETURN allowing different processing of MID and SIDE signals – using mono EQs, compressors, etc.
  • comprehensive MONITORING controls for L and R, or MID and SIDE signals at insert SEND and RETURN points
  • ON/OFF switch bypasses all INSERT functions

Stereo Base

  • Circuitry based on MID/SIDE technique provides continuously variable adjustment starting from center position (STEREO):
    - Narrow STEREO BASE by turning counterclockwise towards MONO.
    - Widen STEREO BASE by turning clockwise towards DIFFERENTIAL signal.
  • Use CONSTANT MID option to “soften” the effect when turning clockwise to DIFFERENTIAL.
  • ON/OFF switch bypasses STEREO BASE stage

Output Stage

Output Stage
  • electronically balanced, max. level > +26dBu
  • OUTPUT GAIN range +/- 10dB, L/R BALANCE range +/- 2,5dB
  • GAIN and BALANCE with trimmed zero position
  • SIGNAL LED (green) level present, individual Left/Right, also monitoring INSERT RETURN
  • O/L LED (red) overload warning, individual Left/Right, also monitoring INSERT RETURN
  • Overall BYPASS, also bridging I/O GAIN stages


To buy a IM1 or ask a question please contact Chris Parkinson below.


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