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Immutable Ears Build Guide

  • 4hp Eurorack contact mic and amplifier

  • Difficulty level: Beginner

  • Time: 1-2 hours

What you'll need

  • Ears DIY kit

  • Soldering Iron

  • Solder

  • Side cutters

Verify parts

  • Begin by pulling out all of the parts included in your ears DIY kit and reference the bill of materials to ensure you're not missing anything

Placing and soldering components

  • Begin by placing the jacks in the orientation shown below, and then soldering them in place from the backside of the PCB

  • Next place the headers. Insert the short ends of the three headers into the backside of the PCB.

  • Solder one pin on each of the three headers and check for alignment of the headers, apply a slight amount of heat to the joint you've just made and push the headers flush to the board and ensure they are standing straight.

LED's and Potentiometer

  • Slide your LED holders onto each of the three LED's.

  • The order of the LED's is dictated by the painted colour on the tips of the LED legs.

  • Red -> LED1

  • White (No Colour) -> LED2

  • Orange -> LED3

  • The LED's will not work if they are not placed with the correct polarity. They must be placed with the short leg (Cathode) facing the top of the PCB and the long led (Anode) facing the bottom.

  • As done with the headers, solder one pin of the LED's then ensure the spacers are flush and straight then finish soldering the rest of the pins in place.

  • Place the potentiometer above the LED's and solder it in place, be sure to use lots of solder on the two larger tabs as they are used to mechanically secure the potentiometer place.

Piezo sensor

  • Place the piezo disk gold side down on the large gold circle that is located on the back of the front panel. Center the piezo with the wires facing upwards on the panel, some masking tape or a light binder clip can be used to hold it in this position.

  • Use your soldering iron to apply heat across the edge of the piezo disk and the pad, apply solder until it begins to flow and a bubble forms across the two surfaces fusing it in place.

  • Ensure the disk is centered and solder two more points along the edge of the disk.

  • Solder the wires to the mic input on the PCB

  • RED (+)

  • Black (-)

Assembly and testing

  • Secure the panel to the board using the nuts for the jacks and the potentiometer

  • Place the jumpers on the bottom headers, these are used to adjust the attack and release time and set the gate threshold voltage for the amplifier.

  • Plug in the power cable with the red stripe facing the red stripe indicator labeled on the back of the PCB.

  • Ensure you're getting audio out of the module by patching the modules output into your mixer and tapping the gold spirals on the front panel, you should hear the tapping and be able to adjust the gain with the potentiometer.

  • The left (red) LED will light when audio is clipping, middle (white) will light with the envelope, and right (orange) will light the the gate is triggered.


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