Doepfer A-150 Dual Voltage Controlled Switch Eurorack Module

Module A-150-1 (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 -12V...+12V 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).

For more detailed information please look at the English user's manual: A150_man.pdf

Similar modules:

• A-151 Quad Sequential Switch
• A-150-8 Octal Manual/Voltage Controlled Programmable Switches
• A-152 Voltage Addressed Track&Hold / Switch (Multiplexer) / Digital Outputs

Technical notes:

• To protect the electronic switches in case of an unsuitable patch (e.g. connection of two outputs) a 1k protection resistor is inserted into the O/I line of each switch. If control voltages used for VCOs are switched this may cause a small voltage drop and lead to undesired audible detuning. For this application we recommend to insert a CV buffer between A-150-1 and the VCO(s), e.g. the modules A-180-3, A-180-4 or the Precision Adder A-185-2. Integrating the buffers into the module A-150-1 is not possible because this would ruin the bidirectionality of the switches.
• Since May 2004 an improved version of the module is manufactured. The revised version allows to process voltages in the full A-100 voltage range (i.e. -12V....+12V). The previous limitation to -8...+8V is no longer valid. The new version can be distinguished from the previous version by the printing at the pcb ("A-150 DUAL VC SWITCH VERSION 2"). Another way to distinguish the two versions are the integrated circuits: "CD4053" for the old version, "DG409" for the new version. Sorry it is not possible to update the old version of the A-150 to the new one as the complete circuit has been changed.

Remark: Module A-150 has been renamed to A-150-1 to distinguish it better from other modules of the A-150 series (e.g. A-150-8)