Andromeda MK-2

Andromeda MK2 assembly guide v2 (green board)

parts identification guide

Description

This was designed as an experiment of making the most minimal drum machine possible using analog circuitry.  Beyond that goal, the design also includes a new feature, IR Sync, which allows a group of these units to all synchronize together and play at the same tempo automatically.  Although the sound of one Andromeda MK machine alone is simple, a group of them together can play more complex rhythms.  The complexity of the patterns is multiplied with each additional unit that is added to the network.  A maximum of 12 units can be connected in a chain.

The Andromeda MK2 analog drum machine has a minimal sequencer with sixteen preset patterns, selectable by the red switch block.  The pushbutton restarts the patterns.  This feature allows you to shift the timing of the rhythm when synchronized with other Andromeda Space Rockers instruments.

The sound of the MK2 is from an analog white noise generator.  This noise is filtered by a resonant filter, and the cutoff of the filter is controlled by the photocell on the left side of the unit.

The sequencer triggers an envelope generator (EG).  This creates a signal that controls the duration and volume contour of the sound.  The EG is controlled by the photocell on the right side of the unit.

The EG’s signal is sent to a voltage controlled amplifier (VCA).  The VCA chops up the steady output from the filtered white noise generator into little bursts of sound, controlled by the EG.  This is what you hear at the output.

Compatible with

• Andromeda MK-1 damped sine wave
  
• Andromeda MK-3 synth pulse (to be released soon)
• Andromeda MK-4 resonant bass drum
• The 4MS Pedals Autonomous Bassline Generator
• MIDI-IR sync converter kit by Wooster Audio.  This kit lets you synchronize your Andromeda Space Rockers with a computer sequencer software, or a hardware sequencer.  It has two sync outputs that can be set to different rhythm intervals, and a “burst” button that plays interesting fills, swing patterns, and syncopations.

Important notes for v2 kits (green board)
There are two 1N914 diodes in the kit.  (the instructions say there is only one)  An 1N914 diode looks like a small red glass cylinder with a black stripe on one end.  This photo shows the locations of the diodes on the board.  Make sure the striped end of the diode matches the printed stripe on the board.

The instruction guide doesn’t mention this - there is an important jumper you have to add for the unit to work.    Look at this photo to see where it goes.  you can use any small piece of uninsulated wire.  I use one of the legs of the components that were trimmed off during assembly.   You can add this jumper as the last step.  The purpose of this jumper is to connect the battery to the jack; thats because the “v2″ PCB was designed for slightly different jacks than are included in the kit.