Doepfer A-183-4 Quad Level Shifter Eurorack Module
Eurorack Level Shifter Module
Module A-183-4 is a fourfold level shifter. A level shifter is required if the level of a digital control signal has to be increased or decreased. It can be used also to improve the slew rate (or edge steepness) of a signal. A typical application is the conversion of a gate, trigger or clock signal with +5V voltage level (or any level beyond +3V) to +12 voltage level. Another application is to sharpen the rising and falling edge of a signal. In some cases (e.g. triggering an envelope generator) a fast rising edge may be required. If the slew rate (and/or level) of the available gate signal is not sufficient module A-183-4 is the right choice.
The output voltage level can be set by means of a jumper to +12V or +5V. The factory setting is +12V. But it can be changed to convert also a higher to a lower level (e.g. +12V to +5V). But this application is required rarely. The output level setting by means of the jumper is global, i.e. it is valid for all four units and cannot be set individually for each unit. A small sticker near the pin header for the jumper tells the two positions for the output voltage (+12V or +5V).
The four output signals are displayed by means of LEDs.
The outputs and inputs of the four sub-units are normalled via the switching contacts of the input sockets, i.e. the output signal of the upper unit is used as input signal of the unit below provided that no patch cable is inserted into the input socket of the lower unit. That way the module can be used also as clock/trigger/gate buffer or buffered multiple for digital signals. For this the signal that has to be buffered is connected to input 1. The buffered (and possible level shifted) signal appears then at all four outputs.
Voltage thresholds for the input voltages:
voltages below +0,8 V are treated as "low"
voltages above +3 V are treated as "high"
Converting the levels of digital control signals (e.g. gate, trigger, clock) to another voltage level (+12V or +5V)
buffering and duplicating digital control signals (e.g. gate, trigger, clock)
improving the edges of "flabby" digital control signals
Important note: the module cannot be used for analog signals ! With an analog input signal the module does work only as a comparator. But in can be used to derive a digital signal with fast slopes from a slowly varying analog signal (e.g. triangle of an LFO). With the aid of an offset generator (e.g. A-183-2) the crossover point can be adjusted.