New Doepfer Eurorack Modules Coming to Superbooth

Details on each below.

"Module A-101-8 is a 8-stage phase shifter which uses light-sensitive resistors (LDR) and is a replica of the Compact Phasing A manufactured by the company Schulte in the seventies. The actual phasing circuit is identical to the historic model. Only the illumination control of the LDRs is different: the A-101-8 uses LEDs to illuminate the LDRs, the historic model used incandescent miniature lamps. And the A-101-8 has no built-in LFO but can be controlled by any external control voltage source (e.g. LFO, ADSR, random, Theremin, ribbon controller, sequencer, midi). The phasing offset (i.e. the base value for the phase shifting) and the modulation depth of the external control signal can be adjusted separately. The Compact Phasing A had no offset control but only a depth control for the built-in LFO. Feedback and mixing ratio of the output signal are set by two controls. The audio input is equipped with an attenuator. The module has two audio outputs available (same as the historic model) and a visual display of the phase shifting."

Module A-135-5 is a combination of a voltage controlled polyphonic mixer and a polyphonic suboctave generator. It is made of 12 voltage controlled amplifiers (VCAs) which are arranged in form of a 4x3 matrix. Herewith up to three four-voice polyphonic signals (e.g. the outputs of three polyphonic VCOs A-111-4) can be mixed. The level of each of the three polyphonic channels (A, B, C) with four voices each can be controlled manually or by means of an external control voltage with associated attenuators. In addition the module features four frequency dividers which derive the suboctaves from the four input signals of channel A. The suboctave signals are wired to the switching contacts of the sockets of channel B. As long as the sockets of channel B are not patched the suboctave signals of channel A are used as inputs for channel B. The suboctaves are symmetrical rectangle waves with half the frequency of the corresponding signal A. For example two polyphonic VCOs A-111-4) can be used and patched to the channels A and C. Channel B then provides the suboctaves of channel A. As the module is fully DC coupled it can be used also for the mixing of control voltages in a polyphonic environment (e.g. for envelopes, LFOs or other control voltages). The switching contacts of the 12 input sockets and the four outputs are internally connected to pin headers. That way the module can be internally pre-patched to other polyphonic modules (e.g. the four inputs A to an A-111-4, the four inputs C to another A-111-4 and the outputs to the polyphonic filter A-105-4). As the switching contacts of the sockets are used for the internal pre-patching the internal patch can be overridden by using the sockets at the front panel.

Module A-147-4 is a dual voltage controlled LFO (Low Frequency Oscillator). Each LFO has the five waveforms triangle, sine, rising and falling sawtooth, as well as rectangle available. The rectangle output features manually adjustable pulsewidth and pulsewidth modulation by means of an external control voltage. The core waveform is triangle. The other waveforms are derived from triangle by means of waveform converters. The frequency of each LFO can be adjusted manually and modulated by means of an external control voltage with associated attenuator and polarity switch. By means of a jumper the basic frequency range of each LFO can selected: about 0.02 Hz (~ 50 seconds) ... 2.5kHz or about 0.0017 Hz(~ 600 seconds) ... 220Hz. That way each LFO can be used also as a VCO with a max. frequency of about 2.5kHz. Each LFO features a reset input which can be used to reset the triangle signal.

Module A-171-4 is a fourfold voltage controlled slew limiter. It's intended purpose is polyphonic portamento but can be used also for other applications where several slew limiters are required. The common slew time can be adjusted manually and in addition controlled by an external control voltage. The module uses light-sensitive resistors (LDR). Therefore the slew times are not exactly the same for all units due to the tolerances of the LDRs and the LEDs, which are used to illuminate the LDRs. Inputs and outputs of the slew limiters are buffered to avoid voltage drops. This is especially important for polyphonic portamento applications. Each output can drive several VCOs without the need of exernal buffers. In addition the slew limiter inputs and outputs are available at internal pin headers for internal pre-wiring of polyphonic patches. As the switching contacts of the sockets are used for the internal pre-patching the internal patch can be overridden by using the sockets at the front panel.