Module A-151 (Quad Sequential Switch) is like an electronic four-position rotary switch.
It includes trigger and reset inputs, four in / outputs, and a common out / input. Each time a pulse is received at the trigger input socket, the common out / input is connected to the next in / output. After the fourth in / output, the next trigger makes it step back to the first again, and so on. A positive pulse at the reset input switches the out / input immediately back to the first in / output (see Fig. 1). Voltages in the range -8V…+8V at the O/I resp. I/O sockets can be processed by the module.
Four LEDs indicate the active in / output (ie. the on that is connected to the out / input at any particular time).
From spring 2005 a revised version of the module is available. With an additional switch the number of steps can be set to 2, 3 or 4 (thanks to Peter Grenader for this idea). Moreover the revised module allows to process voltages in the full A-100 voltage range (i.e. -12V…+12V). The limitation to -8V…+8V is no longer valid. While stocks last the user can choose between version 1 and 2. Version 1 will be no longer manufactured in the future. The A-100 DIY page describes how to install this additional switch for the old version of A-151..
For more detailed information please look at the English user’s manual: A151_man.pdf.
Similar modules: A-152 Voltage Addressed Track&Hold / Switch (Multiplexer) / Digital Outputs
Technical note: 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. 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-151 and the VCO(s), e.g. the modules A-180-3, A-180-4 or the Precision Adder A-185-2. Integrating the buffer into the module A-151 is not possible because this would ruin the bidirectionality of the switches.
Width: 4 HP / 20.0 mm
Depth: 35 mm (measured from the rear side of the front panel)
Current: + 20 mA / – 10mA