A-114 - Synthesizer Doepfer - Free user manual and instructions

Product Type	Eurorack Synthesizer Module
Model	A-114
Brand	Doepfer
Function	Dual Ring Modulator
Width	8 HP (40.3 mm)
Depth	40 mm (approx.)
Weight	80 g (approx.)
Power Supply	+12V: 20 mA, -12V: 20 mA
Power Connector	16-pin ribbon cable (Doepfer standard)
Audio Inputs	2 x 3.5 mm mono jacks (modulator 1 & 2)
Carrier Inputs	2 x 3.5 mm mono jacks (carrier 1 & 2)
Audio Outputs	2 x 3.5 mm mono jacks (output 1 & 2)
Front Panel Material	Aluminum, 2 mm thickness
Circuit Board	FR4, double-sided, plated through holes
Operating Temperature	10°C to 40°C
Humidity	0% to 85% (non-condensing)
Maintenance	Clean with soft dry cloth; avoid liquids
Safety	Disconnect power before installing or removing modules
Spare Parts	Not available; contact Doepfer for repairs
Warranty	2 years from date of purchase

Frequently Asked Questions - A-114 Doepfer

What is a ring modulator and what is the A-114 used for?

A ring modulator is a circuit that multiplies two audio signals, producing sum and difference frequencies. The Doepfer A-114 is a dual ring modulator module, great for creating metallic, bell-like, or robotic sounds, as well as frequency shifting effects.

How do I power the A-114 module?

Connect the included 16-pin ribbon cable to your Eurorack power bus board, ensuring the red stripe aligns with the -12V rail. The module requires +12V 20mA and -12V 20mA.

What are the audio input and output levels?

The A-114 accepts and outputs Eurorack-level audio signals, typically around ±5V to ±10V peak-to-peak. For best results, keep levels within the modular standard.

Can I use the A-114 for CV signals?

Yes, you can use control voltages as inputs, but the circuit is designed for audio. Applying CV will produce amplitude modulation effects. For CV processing, use a dedicated VCA or mixer.

How do I connect the A-114 in my system?

Patch an audio source (e.g., VCO output) to the Audio Input and another signal (e.g., another VCO, LFO) to the Carrier Input. The Output will contain the ring-modulated result. The module has two independent ring modulators.

What is the frequency response of the A-114?

The A-114 has a frequency response from about 20 Hz to 20 kHz, suitable for full audio range operation. It uses precision resistors and matched transistors for clean multiplication.

Is the A-114 compatible with other Eurorack cases?

Yes, as a standard Doepfer module, it fits any Eurorack case with a 16-pin power header. The width is 8 HP (40.3 mm), so ensure your case has enough space.

How do I clean the module?

Turn off power and disconnect the module. Gently wipe the front panel with a soft, dry cloth. Do not use solvents or water. For jacks, use a contact cleaner only if necessary.

Can I build a patch with feedback using the A-114?

Yes, feedback patches are possible. Route the output back into an input (via a mixer or attenuator to control level). This can create unstable, chaotic sounds reminiscent of oscillators.

What should I do if the module does not work?

First, check power connections (red stripe orientation). Verify that the power supply provides adequate current. If issues persist, contact Doepfer support or your dealer for warranty service. Do not attempt repairs yourself.

USER MANUAL A-114 Doepfer

1. Introduction

Module A-114 (Dual Ring Modulator) contains two separate ring modulators.

A ring modulator outputs the product (Multiplication X • Y) of the signals at inputs X and Y. It's similar to a VCA, but whereas a VCA only responds to positive voltages at the inputs (2-quadrant multiplication), the ring modulator responds to both positive and negative voltages (4-quadrant multiplication).

The ring modulator thus provides a refinement of amplitude modulation (AM). Ordinary amplitude modulation will output the original carrier frequency f_c as well as the two side bands ( f_c - f_M, f_c + f_M ) for each of the spectral components of the carrier and modulation signals - but ring modulation cancels out the carrier frequencies, and just lets the side-bands pass to the output (see Fig. 1).

A ring modulator is used for the production of bell-like sounds, alien voices, or just to produce new timbres.

2. Dual Ring Modulator - Overview

In / Outputs:

① X In : Signal input
② Y In : Signal input
③ X*Y Out : Output

3. In / Outputs

① X In • ② Y In

Sockets ① and ② are the signal inputs for the A-114. Patch the signals you would like to ring modulate into these sockets.

The inputs need to have AC signals - so you should use audio signals, not control voltages. For control voltages, use a VCA.

③ X\*Y Out

Socket ③ is the ring modulator Output.

4. User examples

Basic ring modulation

Fig. 1 shows a basic form of ring modulation using two sine waves. This patch can provide bell- and vibes - like sounds.

Fig. 1: Ring modulation with two sine waves

Ring modulation of audio signals

A ring modulator is very good at doing weird things to audio signals (for instance, voices, strings, sax).

The example at Fig. 2 shows an audio signal (input via module A-119 "Ext. In") ring modulated with a sine wave. The spectrum at the output contains the sum and difference of the frequency of the sine wave with every single one of the components of the audio signal's sound spectrum.

graph LR
    A["VCO"] --> B["A-114"]
    C["A-119"] --> D["Audio Out"]
    C --> E["Env. Out"]
    B --> F["RNG MOD"]
    B --> G["X IN"]
    B --> H["Y IN"]
    B --> I["X·Y OUT"]
    D --> J["VCA"]
    E --> J
    F --> J
    G --> J
    H --> J
    I --> J
    J --> K["Output"]

Fig. 2: Ring modulation of an external audio signal.

In this patch, the A-119 performs two functions.

On the one hand, it's bringing the level of the external signal up to the A-100's operating level (round about 5 V_ss ).

On the other hand, it's also sending the envelope follower output (the envelope generated by the external audio signal) to a VCA. This is necessary because the ring modulator doesn't completely shut off when there's 0V input. The VCO is still just audible, at approximately -50 to -60dB, even when there's no external audio signal. The VCA gates it completely.

Experiment with this set-up, for instance by replacing the sine wave with other waveforms (eg. sawtooth, square wave, etc.)

The waveform you use can itself also be modulated (for instance by PWM, AM, FM, or audio signal).

"Glissando ring modulation"

The patch in Fig. 3. produces some interesting sounds. Input two VCOs set to an exact harmonic interval (eg. a fifth or octave) into the ring modulator. Send the pitch CV direct to the first VCO, but run the second oscillator's CV through the upper section of the slew limiter (A-170) first.

Whenever the pitch CV changes, the ring modulation causes gradual changes in the sound spectrum.

graph TD
    A["Gate"] -->|CV| B["VCO 1"]
    A --> C["A-170"]
    B --> D["A-114 RNG MOD\nX N\nY N\nX·Y OUT"]
    C --> E["VCA"]
    D --> F["VCA"]
    E --> F
    F --> G["Output"]

Fig. 3: "Glissando ring modulation"

Use the upper part of the A-170 for this, because the diode offset in the lower part will put the VCO out of tune.

A-114 Dual Ring Modulator

System A - 100

DOEPFER

5. Patch-Sheet

The following diagrams of the module can help you recall your own Patches. They're designed so that a complete 19" rack of modules will fit onto an A4 sheet of paper.

Photocopy this page, and cut out the pictures of this and your other modules. You can then stick them onto another piece of paper, and create a diagram of your own system.

Make multiple copies of your composite diagram, and use them for remembering good patches and set-ups.

- Draw in patchleads with colored pens.