Bipolar Rectifier and Limiter

https://www.kickstarter.com/projects/1411638041/archimedes-a-bipolar-cv-modulator-and-limiter-euro

Archimedes is a Bipolar Dynamic Signal Manipulator.

It is designed to take in a +5 / -5 volt signal (Oscillator, LFO, Noise, Random) and process the positive and negative sections separately with lots of CV control that’s AC / DC capable. There is no filtering on all of the inputs or ouputs on Archimedes, so you can get your BDSM on, proper.

It is comprised of 3 linear sections:
2 Bipolar Rectifiers -> Offset -> 2 Bipolar Limiting Rails

Archimedes has 5 knobs that feed +5 / -5 volts into their appropriate sections, but when a respective CV Input is used the internal voltage controlling the knob will be disconnected and the knob will turn into an an attenuverter.

Archi works by separating the positive and negative sections of the input signal and runs each of them into their own four quadrant multiplier. This allows you to have half-wave rectification over the positive and negative sections of the input signal, which are available as separate half-wave rectified outputs (POS and NEG). You can get a full-wave rectified version of the input signal by using the OFFSET output or the main OUT.

The POS REC CV and NEG REC CV inputs use +5 / -5 volts for “polar flipping.” Set both REC section knobs to fully clockwise. This is the “true” position, as indicated by the picture on the front panel. When the REC knobs are set to fully counter clockwise, they are inverting the signal, also indicated by the picture on the front panel.

To close the POS REC and NEG REC sections to 0 volts like a VCA, use 0 - 5 volt envelopes, or attenuate the signal with the respective knob. While the POS REC CV and NEG REC CV inputs can handle over 5 volts, they will clip just over 6 volts which may or may not be to your liking.

The 2 separate four quadrant multipliers then sum together at a node where there is a convenient +5 / -5 volt OFFSET knob. This allows you to shift the input signal to +10 -> 0 volts or 0 -> -10 volts. The OFFSET output is capable of passing +10 / -10 volts, though will clip if exceeded.

The OFFSET section then runs into the last section of Archimedes, the Bipolar Limiting Rails. These rails sit barely above +5 volts and just below -5 volts. These “rails” will not pass any signal over their standing position. This allows you to dial in modulation in critical areas and get some pretty brutal distortion. The POS and NEG CLIP lights will turn on whenever the rails are clipping.

The POS RAIL CV and NEG RAIL CV inputs use +5 / -5 volts for “bipolar limiting.” Set both RAIL section knobs to fully clockwise. This is the “true” position, as indicated by the picture on the front panel. When either of the RAIL knobs are set to fully counter clockwise, it brings the limiting rail past 0 volts and into the opposite section, also indicated by the picture on the front panel. This means you can take the Positive Rail and move it into the negative section of the input signal, and vice versa. The rails can influence each other when they collide, and when they move they can produce an offset effect.

To close the POS RAIL and NEG RAIL sections to 0 volts like a VCA, use 0 - 5 volt envelopes, or attenuate a hotter signal with the respective knob. The limiting rails can operate at higher than 5 volts when using an external offset or signal that is 0 - +10 volts. The main OUT output is capable of passing +10 / -10 volts, though will clip if exceeded.

http://metzgertechnologies.com/archimedes

  • 90 mA +12V
  • 90 mA -12V
  • ? mA 5V
  • 38 mm Depth

This module is a prototype or in a concept phase.

$200 submitted Mar 18th, 04:35 by biltmore | last Change Mar 20th, 20:28 by biltmore

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