Ears - Audio accessory Mutable Instruments - Free user manual and instructions

Type	Contact microphone module for Eurorack
Dimensions	4 HP (approx. 20 mm wide)
Depth	32 mm
Weight	50 g
Power supply	+12V and -12V via Eurorack bus board
Current draw	+12V: 10 mA, -12V: 5 mA
Inputs	1x 3.5mm mono jack for external signal (preamp mode)
Outputs	1x 3.5mm mono jack (envelope follower output), 1x 3.5mm mono jack (audio output)
Main functions	Contact microphone preamplifier, envelope follower, gate extractor
Controls	Gain trim pot, sensitivity trim pot, threshold trim pot
Indicators	LED for gate/trigger status
Materials	PCB with RoHS compliant components, aluminum front panel
Compatibility	Any Eurorack case with standard power header
Operating temperature	0°C to 50°C
Storage temperature	-20°C to 60°C
Maintenance	Keep dry; clean front panel with a soft cloth
Safety	Do not exceed ±12V supply voltage; connect/disconnect only when power is off
Repairability	DIY-friendly through-hole components; schematics available online
Additional information	Includes piezo contact microphone element with adhesive pad

Frequently Asked Questions - Ears Mutable Instruments

What is the Mutable Instruments Ears module?

The Ears is a contact microphone preamplifier and envelope follower module for Eurorack synthesizers. It amplifies signals from piezo contact microphones and provides envelope and gate outputs for processing external sounds.

How do I power the Ears module?

Connect the module to your Eurorack case's bus board using the included 10-pin ribbon cable. Ensure proper orientation: the red stripe indicates -12V. It requires +12V (10 mA) and -12V (5 mA).

Can I use Ears without a contact microphone?

Yes, the module has a 3.5mm input jack for external line-level signals. You can use it as a preamp/envelope follower for any audio source, such as a microphone or instrument pickups.

What outputs does Ears provide?

It has two outputs: an audio output (the amplified signal) and an envelope follower output (a CV representing the amplitude envelope). There is also a gate output that goes high when the signal exceeds a threshold.

How do I adjust the sensitivity?

Use the three trim pots on the module: Gain adjusts overall amplification, Sensitivity sets the envelope follower response, and Threshold sets the level at which the gate triggers. Turn them with a small screwdriver.

Is the piezo contact microphone included?

Yes, the Ears module comes with a piezo contact microphone element that has a self-adhesive pad for attaching to surfaces like instrument bodies, glass, or metal.

Can I use Ears as a regular preamplifier?

Yes, the audio output provides a clean amplified signal. You can connect it to your mixer, audio interface, or another module. The gain can be adjusted to match different sources.

What is the size of the Ears module?

It is 4 HP wide (about 20 mm) and fits all standard Eurorack cases. The depth is 32 mm, so ensure your case has enough clearance.

How do I clean and maintain the module?

Keep the module dry and free from dust. Wipe the front panel with a soft, dry cloth. Do not use solvents or abrasive cleaners. Avoid touching the circuit board.

Where can I find schematics or repair information?

Mutable Instruments provides open-source documentation. Schematics, PCB layouts, and firmware are available on their official GitHub repository. The module is designed for easy DIY repair with through-hole components.

USER MANUAL Ears Mutable Instruments

Our take on Tom Whitwell's Mikrophonie module, Ears is a perfect match for physical synthesis modules like Rings or Elements, but it can also be the gateway between external audio sources and your modular system.

Installation

Ears requires a -12V / +12V power supply (2x5 pin connector).

The ribbon cable connector must be aligned so that the red stripe of the ribbon cable (-12V) is on the same side of the module's power header as the "Red stripe" marking on the board. The module draws 5mA from both the +12V and the -12V supply rails.

The full manual can be found online at mutable-instruments.net/modules/ears/manual

For help and discussions, head to mutable-instruments.net/forum

FC CE

Please refer to the online manual for detailed information regarding compliance with EMC directives

Mutable Instruments

Abstract pink square icon with concentric circles and a central dot (no text or symbols)

Ears

Contact microphone

Illustration of a fingerprint pattern on a surface with three colored dots (red, yellow, orange) and a white cylindrical object on top (no text or symbols)

A. Gain control, 0 to 40dB (loud! may cause clipping).
B. Contact microphone.

1. Hi-Z Audio input. Amplifies an external source. Patching a cable here disconnects the contact microphone.
2. Audio output. The red LED indicates clipping.
3. Envelope CV output. The white LED indicates the envelope CV level.
4. Gate output. Emits +8V when the envelope exceeds a threshold. Indicator: orange LED.

The jumpers at the back of the module adjust the response of the envelope follower and gate detector.

Envelope Follower

Gate Detector

The last setting is obtained by removing the jumper.