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mami

atoav's avatar
Swapped R4 and R8 for 100 Ω
David Huss authored 
This fixes an error where `R4` and `R8` had mistakingly a value of 100
kΩ. If you don't have a 100 Ω 0805 resistor at hand, you can bridge this
one instead.
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Name Last commit Last update
gerbers
horizon
images
panels
README.md
calculate-parts.ipynb
mami-input_schematic.pdf
mami-output_schematic.pdf
mami-quad_schematic.pdf
README.md

MAMI - Matrix Mixer

A set of modular PCBs that can be used to create a custom configuration for a Matrix Mixer. A Matrix mixer allows you to mix you any input to any output at the same time.

If you have for example a 4x4 Matrix Mixer, you have 16 knobs with each controlling a how much of a given input signal (1-4) will be mixed into a given output (A-D):

For example by turning up the knob at the intersection between Input 2 and Output B we can mix all of the signal present at the input to the output. If we turn up another knob at another intersection, the signal will be present at both outputs:

This makes Matrix mixers extremely flexible and allows for many possible combinations and use cases.

Modules

The 4x4 matrix above consists of:

  • 2x MAMI-INPUT Module
  • 2x MAMI-OUTPUT Module
  • 4x MAMI-QUAD Module

The modules are designed in a way they can be connected via wires or jumpers to each other, so multiple configurations are possible (e.g. 2x2, 2x4, 4x2, 8x8, 10x6 etc.).

Here an example 8x8 setup consisting of 4 Input modules, 4 Output modules and 16 Tiles:

Example 8x8 setup consisting of 4 Input modules, 4 Output modules and 16 Tiles

Input Module [MAMI-INPUT]

The Input Module has two 3.5mm Mono Input Jacks and two (On)-Off-On Switches that allows muting individual inputs (or momentarily/permanently switching them on).

Top Bottom 3D

2x2 Tile Module [MAMI-QUAD]

Mixes two inputs onto two outputs using 4 Potentiometers.

Top Bottom 3D

Output Module [MAMI-OUTPUT]

Provides two 3.5mm Mono output jacks, with a Jumper (or switch) each row of tiles can be switched between unipolar and bipolar attenuation.

Top Bottom 3D

The summing section looks like this and allows a jumper (J_ATT1 and J_ATT2) or a switch (2.54mm lead spacing) to be used to switch between unipolar and bipolar attenuation for each row seperately.

Erata Output Module rev. 1.0 (fixed in 1.1)

  • Silkscreen for Vee and Vcc is swapped!
  • R4 and R8 should have a value of 100 Ω not 100 kΩ (or bridge it with solder)

Panels

Constructing a panel is straightforward: drill holes for all potentiometers, switches and jacks. There is an example panel for a 8x8 Matrix in the panels directory.

Parts/BOM

Use the python code in calculate-parts.ipynb to calculate the needed parts for your variant of the MAMI

Power-Supply

The MAMI needs a fitting ±12V Power supply. This obviously depends on the size you are going for. Anything up to 10x10 should be able to be powered by the 3WPSU with a USB-B Phone Charger as one output module should use about 10mA (to be verified) and the 3WPSU is able to deliver up to 125mA per rail.