Tags: Attenuator module

Notes: Each of the two sections of the module is capable of performing the analog multiplication of two signals (A and B) and add an offset (C). It can also act as a dual voltage controlled attenuverter, dual ring modulator, dual VCA or four channel mixer (see block diagram below).

The B inputs are routed to an attenuverter that multiplies the signal between -2 to 2, while the offset inputs (C) route through a unity gain attenuverter (multiplies the signal between -1 and 1).

The output of first section is routed to the output of the second (when the first's output is unused), so the second output can act as master to achieve (A1*B1+C1) + (A2*B2+C2) or (A1 + C1) + (A2 + C2) - a 4 channel mixer.

The through-zero (four-quadrant) multipliers in the A*B+C allow for true Ring Modulation. To achieve this, simply connect two waveforms to the A and B inputs.

Notes: Arkan

Dual Voltage Polarizer

You may have heard this before: "You can never have enough VCAs". A voltage polarizer (also known as a bipolar VCA or a 4-quadrant multiplier) is often viewed as the VCA better suited for CV. As it can be used as a unipolar VCA and it allows you to invert a signal when it is modulated with a negative voltage. Resulting in interesting movements in your modulations.

What sets Arkan apart from other voltage polarizers is the curvature control, a feature usually only seen in unipolar VCAs. By taking a different approach to the classic voltage polarizer circuitry, Malstrom have devised a unique solution that provides a new way to shape your audio and CV. The non-linearity of the polarizer also makes Arkan really good at reaching silence when presented with a 0V CV signal.

At audio rate, Arkan acts as a ring-modulator with four controls to change timbres.

Boosting adds odd harmonics (symmetrical distortion), while offsetting adds even harmonics (asymmetrical distortion). The modulation curve changes ring modulation sharpness, and modulation strength determines the carrier dominance.

Two identical channels with carefully selected features will make Arkan your go-to modulation control hub. Arkan is especially useful for common utility duties such as mixing, scaling, inverting and offsetting. As well as CV modulation, feedback patching, and waveshaping. All this makes Arkan a very versatile tool that will certainly have a place in your patch!

Features (per channel)

- Input attenuation with inverter switch gives you more precision and range, with voltage inversion and quick silencing.
- Bias input with attenuverter control to offset your input signal or mix/invert another signal.
- CV input with curvature control allows you to shape the polarizer and improve its 0V attenuation.
- CV modulation control to fade in the modulator, allowing you to determine the amount of modulation.
- Voltage gain and polarity led indicators showing you exactly what is happening under the radar.
- Output normalled internally and externally (to other Arkans) to easily mix signals.

Additional features

Optional signal boost (x4 / +12dB) via switch on the PCB to increase voltages when needed.
5V or 10V voltage reference selection for bias voltage and CV input range to adjust Arkan to your system.

Dimensions
- 8HP.
- 28mm, Skiff-friendly.

Power consumption
- 90mA @ +12V.
- 85mA @ -12V.

I/O specs

- All inputs DC coupled.
- All inputs handle audio signals.
- All inputs have 100k input impedance. - All inputs have +-10V Input range.
- CV range +-5V or +-10V.
- Bias Voltage range +-5V or +-10V.
- Boost gain x1 or x4.
- All inputs are overvoltage protected.
- Keyed power header.
- Reverse power protection.