The Gristleizer

The Gristleizer Eurorack Module. This version features a totally redesigned filter, more controls, and expanded CV capabilities.

The Gristleizer is a legendary VCA/VCF effect used extensively by industrial music pioneers Throbbing Gristle. Developed by a 15 year-old Roy Gwinn and published in a DIY electronics magazine in 1975, the original design found its way to Throbbing Gristle, who brought the Bias trimpot to the front panel and dubbed it The Gristleizer.

Decades later, Endangered Audio Research released the first production Gristleizer tabletops, which faithfully recreated the circuit while solving many of the problems inherent in the original design.

Now, after 8 years of continuous refinement, including a major overhaul of the filter circuit,
expanded controls, and more CV options, Endangered Audio Research presents the Eurorack version of The Gristleizer. This is an extremely limited run, after which The Gristleizer name will be retired from the Endangered Audio Research product line permanently.

Features:

Knobs:

BIAS - In VCA mode, the Bias effects the intensity and shape of the modulation, amount of distortion, and overall level of the modulated signal.
GAIN - Controls the amount of signal drive in the first gain stage.
FILTER MIX - Controls the amount of dry signal added to the filtered signal.
FREQ - Controls the frequency of the internal LFO.
DEPTH - Controls the amount of LFO modulation applied to the signal.
LEVEL - Controls the output level of the module.

Switches:

MODE SWITCH - Selects VCA or VCF mode.
IN/OUT SWITCH - True bypass switch.

Light:

LED - Indicates the rate of the internal LFO. A specially selected Frensel LED and lens provides a convincing incandescent look.

Jacks:

IN - Signal to be Gristleized.
OUT - Gristleized signal (when effect is switched in).

BIAS IN - Allows for external control of the Bias voltage. Can be modulated by any signal of sufficient strength. This is a switching jack - when patched, it disconnects the BIAS knob on the front panel.
BIAS MIX IN - Same as the BIAS IN, but does not disconnect the front panel BIAS control. Instead, the external input is mixed with and scaled by the BIAS knob.

FREQ IN - Allows for external control of the LFO frequency. This is a switching jack - when patched, it disconnects the FREQ knob on the front panel.
FREQ MIX IN - Same as the FREQ IN, but does not disconnect the front panel FREQ control. Instead, the external input is mixed with and scaled by the FREQ knob.

MOD IN - This switching jack is normaled to the Triangle LFO, meaning you do not need to patch the module for it to function. Inserting a patch cable will break this connection and allow you to modulate The Gristleizer with any modulation source, including LFOs, envelopes, sequencers, sample & hold, and audio.

TRIANGLE OUT - Triangle LFO
SAWTOOTH OUT - Saw LFO
SQUARE OUT - Square LFO - not a true square wave, but optimized with sloping rising and falling edges to prevent the clicking that plagues the original design.

http://www.endangeredaudioresearch.com/shop/the-gristleizer-eurorack-module-pre-built/