Eurorack Module

Pre

Low Noise Preamp for Microphones and Pickups

The Pre module allows the embedding of signals from electro dynamic sound sources such as microphones or pickups (e.g. e-guitars) in modular synthesizer equipment. Its high amplification together with a very low noise floor allows the processing of even very low input signals (such as from dynamic microphones). The module is equipped with a ‚Sensitivity‘ knob to adapt it to different input levels, coming from different pickups or microphones. A red LED indicates when the level is overdriven, causing the signal to become saturated; here the preamp soft clips the signal. Additionally, a trimmer on the back of the module allowes the setting of the max. output gain – between 3Vpp and 18Vpp. Further, there is a jumper to optionally supply an electret microphone with +12V power supply, provided on the middle ring of a 3-pole jack.
From Rev.2, there is a 2nd minijack/banana input which may be alternatively used instead of the 1/4′ jack input; it will be switched off when a plug is applied to the main input jack.

Minijack

• Very low noise

• Adjustable input sensitivity

• Soft clipping behaviour with red indicator LED

• Output gain trimmer (max. output signal ca 18Vpp)

• Optional +12V power supply for electret microphones

• Available with banana or 3,5mm minijacks

• Eurorack module

• Width: 5 HP

• Dimensions: 128,5 mm x 25,2 mm

• Depth: 40mm

• Supply voltage: ±12V

• Current consumption (postive rail, without load): ≈10mA

Documentation

PDF Download

Panel

Side view right I

Side view right II

Side view left

Side view banana

1. Pre & XR22VCO FT

The Pre’s output is connected to the
XR22VCO’s AM input. The oscillator is amplitude-modulating the microphone signal and vice versa (ring modulation with oscillator tone)

Pre In: Microphone with trumpet
XR22 VCO: Different frequency settings

2. Pre & Delay1022

The Pre’s output is connected to the Delay1022 input ‚In1‘.
Delay, phasing and flanging effects.

Pre In: E-guitar
… Delay1022 T CVin: Sinewave Oscillator

3. 2x Pre & X multiplier

Ringmodulation of 2 acoustic signals (from e.g. 2 different microphones, 1 instrument pickup & 1 microphone etc.).

Pre1 In: Microphone with voice…with harmonica
Pre2 In: E-Guitar

4. Pre & PEAK+HOLD

The PEAK+HOLD’s 1/4′ jack input is optimized for higher signal levels coming from pickups mounted on a drum, so a preamp is needed if the P+H module shall be sourced from a microphone.

Pre In: Microphone with voice…with bongos/cymbal
PEAK+HOLD CV outs controlling XR22VCO and Delay1022