A-150 - Uncategorized Doepfer - Free user manual and instructions

Product Type	Eurorack Module
Model	A-150
Brand	Doepfer
Width	8 HP (approx. 40.3 mm)
Depth	Approx. 50 mm (with power cable)
Weight	Approx. 80 g
Power Supply	+12V: 30 mA, -12V: 10 mA (typical)
Functions	Dual voltage controlled switch (VCS)
Control Voltage Range	0V to +10V (standard Eurorack)
Switching Threshold	Approx. +1.5V
Audio/CV Inputs	Two signal inputs per switch (IN1, IN2) and one common output (OUT)
Control Input	CV input for switch position
Output Impedance	Low, suitable for patching
Protection	Reverse power protection (shunt diode)
Maintenance	Keep module clean and free of dust; avoid moisture
Cleaning	Use a soft, dry cloth. Do not use solvents.
Safety	Disconnect power before installation. Handle with care.
Spare Parts / Repairability	Contact Doepfer or authorized dealers for service
General Information	Part of the Doepfer A-100 modular system

Frequently Asked Questions - A-150 Doepfer

What is the Doepfer A-150 module used for?

The A-150 is a voltage controlled switch (VCS) that routes two inputs to one output based on a control voltage. It is ideal for switching audio or CV signals in a modular synthesizer.

What is the CV range for the control input?

The CV input accepts signals from 0V to +10V. The switch toggles at approximately +1.5V.

How do I connect the power?

Connect the supplied ribbon cable to the Eurorack bus board. Ensure the red stripe aligns with the -12V rail as indicated on the module's PCB.

What is the power consumption of the A-150?

It typically consumes 30 mA on +12V and 10 mA on -12V.

Can I use the A-150 for audio signals?

Yes, it handles both audio and CV signals with low distortion and high fidelity.

What is the width of the module?

It is 8 HP wide (approx. 40.3 mm).

How do I clean the module?

Use a soft, dry cloth to wipe the front panel. Avoid liquids or abrasive cleaners.

Is the module protected against reverse power?

Yes, it has a shunt diode for reverse polarity protection.

What is the output impedance?

The output impedance is low, suitable for driving other modules without signal degradation.

Where can I find the manual or support?

The manual is available on notice-facile.com or the Doepfer website. For technical support, contact Doepfer or an authorized dealer.

USER MANUAL A-150 Doepfer

1. Introduction

Module A-150 (Dual VCS) contains two separate voltage-controlled switches.

Each switch has a control voltage input, a common Out / Input, and two In / Outputs. The switches are bi-directional: they can work in both directions, so can connect one input to either of two outputs, or either of two inputs to one output. Voltages in the range -8V...+8V at the O/I resp. I/O sockets can be processed by the module.

Two LEDs show which in / output is active (ie. which is connected to the common out / input).

From about March 2004 a new version of the A-150 is available. This allows the full A-100 voltage range -12V...+12V for the voltages at the O/I resp. I/O sockets. The new version can be identified at the pc board label "A-100 SYSTEM A-150 DUAL VC SWITCH VERSION 2" near the bus connector at the pc board edge.

2. Overview

Indicators:

① LED: indicator for in / output ②
② LED: indicator for in / output ③

In / Outputs:

① CV : input for digital control voltage
② I/O 1 : in / output 1
③ I/O 2 : in / output 2
④ O/I : common out / input

3. Indicators

① LED ... ② LED

LEDs ① and ② serve as status indicators, to show which of the two in / outputs ② and ③ is at that moment connected to the common out / input ④.

4. In / Outputs

① CV

Socket ① is the input for the digital control voltage, whose level determines the switch state (see Fig. 1):

• CV low (< \~3.6 V): O/I ---- I/O 1
• CV high (> \~3.6 V): O/I ---- I/O 2

If a high frequency control voltage is used for switching, audio frequency modulation results (see Fig. 4 on page 5).

Fig. 1: The A-150's switching behaviour

② I/O 1 • ③ I/O 2

These sockets are the in / outputs.

④ O/I

Socket ④ is the common out / input. Depending on the level of control voltage at input ① it's connected to socket ② or ③ (see Fig.1).

The switches are bi-directional: that is, two inputs can be connected to one output, and vice versa. The particular arrangement of inputs / outputs will always be clear from looking at what is patched to which socket.
Any signal from -8 V to +8 V can be controlled by the A-150. Voltages less than -8V or more than +8V will lead to malfunction of the module! It is possible to modify the module so that voltages in the range 0...+12V can be processed. You find a modification of the A-150 for signals in the range 0...+12V on our web site www.doepfer.com in the FAQ section (click to the FAQ button on the left side of the page).
Another solution for signals beyond -8V resp. +8V is to attenuate and/or to change the offset voltage of the signal. The A-129/3 attenuator/ offset generator can be used for both purposes.
From about March 2004 a new version of the A-150 is available. This allows the full A-100 voltage range -12V...+12V for the voltages at the O/I resp. I/O sockets. The new version can be identified at the pc board label "A-100 SYSTEM A-150 DUAL VC SWITCH VERSION 2" near the bus connector at the pc board edge.

5. User examples

Switching filter characteristics

In the example in Fig. 2, with the help of an A-150, a signal can be switched between a 12dB and 24dB low pass filter.

The control voltage CV_s can for instance come from the CV output of a MIDI-CV interface (e.g. A-191), so that, for instance, a MIDI controller could be assigned to switch between filter types.

graph TD
    VCO --> A120
    VCO --> A121
    A120 --> A150
    A121 --> A150
    A150 --> VCA
    A150 --> CVs
    A150 --> I/O1
    A150 --> I/O2
    A150 --> OI

Fig. 2: Switching between two filters with the A-150

Switching between modulation sources

In the example in Fig. 3, the A-150 switches between two filter cut-off modulation sources. The control voltage CV_s (for instance from a MIDI controller) determines whether the ADSR (when CV_s = 0 V ) or the output from the mod wheel CV_M (when CV_s = +5 V ) controls the cut-off frequency of the filter.

graph TD
    A["VCO"] --> B["VCF"]
    B --> C["VCA"]
    D["Gate"] --> E["ADSR"]
    F["CVs"] --> E
    G["CVM"] --> H["A-150"]
    H --> I["CV"]
    H --> J["VO 1"]
    H --> K["VO 2"]
    H --> L["Q/I"]

Fig. 3: Switching between modulation sources

Switching by audio-range signals

In Fig. 4, the A-150 is set up to switch the audio output of a VCO. The switching voltage is provided by the VCO's square wave output, with the result that at each half cycle, synchronised to the VCO frequency, the waveform changes to sawtooth. Try variations on this patch, with an independent VCO or LFO providing the switching voltage, different frequencies, etc..

Fig. 4: Audio-range switching of an audio signal

A-150 Dual VCS

System A - 100

DOEPFER