MSK 015 Quad VCA

US$446.42 including shipping

Never run out of VCAs again

So you're patching your synthesizer, deep into a groove, and you run into a wall: not enough VCAs. We've all been there. Whether adding a voice, bringing in a modulation source, modulating the modulators, or panning signals around in stereo or quadraphonic sound, every new patch idea seems like it calls for just one more voltage-controlled amplifier.

This module gives you four. Four clean general-purpose VCA channels based on the Alfa AS3360 chip, with normalling between the channels to make stereo patching convenient. It's easy to build cross-fade and panning patches with the separate inverting and non-inverting control voltages on each channel. The global mix output works for combining voices, and there are two sets of two-channel sum and difference outputs, allowing the Quad VCA to serve as a mid-side encoder and decoder. The normally two-quadrant VCA channels can even be used in pairs for two four-quadrant ("ring mod") multipliers. With so many ways to use it, the Quad VCA could be the only VCA module needed in a small portable rack, or the heart of a complex patch in a large installation.

North Coast's Quad VCA is available as a pre-built 20HP Eurorack module or a DIY kit. Remove the limits.

Four channels of voltage-controlled amplification, each with an inverting and a non-inverting control input.
Separate offset knobs go a little below zero, so you can cancel the "bleed" effect from small CV offsets introduced by other modules.
Semi-permanently configurable (via DIP switch on the back) for exponential or linear mode, per channel.
Individual channel, four-way master sum, and two two-way sum and difference outputs.
No compromises on build quality: real aluminum panel, not PCB material, with colour printing; long-life conductive plastic potentiometers, fastened to the panel; nickel and gold plating on the circuit boards; close-tolerance metal film fixed resistors.
Through-hole for easy hand construction and maintenance
Fully open design - no lock-in

Specifications

20HP Eurorack synthesizer module, 42mm deep including space for the power cable.
DC-coupled and suitable for audio or control signals.
Adjusted for accurate unity gain at +5V effective control voltage in linear mode. Gain continues above unity to about +8V. In exponential mode, gain is about 12dB/volt with unity at +5V.
Maximum current requirements in normal use: 55mA +12V, 50mA -12V. Reverse-power and missing-rail protected.
Build difficulty: intermediate. All through-hole. Multimeter and fixed voltage source recommended for adjustment.